Multi-speed gearbox with high torque ratio and the drive axle made therewith

ABSTRACT

An electric drive axle assembly of a vehicle includes an electric motor having an output shaft. At least one of a gear and a planetary gear assembly is coupled to the output shaft of the electric motor. The at least one of the gear and the planetary gear assembly is coupled to a differential mechanism configured to transfer torque to two axle shafts of the vehicle. The electric drive axle assembly configured to produce a plurality of speed ratios between the electric motor and the differential mechanism.

RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 16/443,099, entitled “MULTI-SPEED GEARBOX WITH HIGH TORQUERATIO AND THE DRIVE AXLE MADE THEREWITH,” and filed on Jun. 17, 2019.U.S. patent application Ser. No. 16/443,099 claims priority to U.S.Provisional Patent Application No. 62/685,766, entitled “MULTI-SPEEDGEARBOX WITH HIGH TORQUE RATIO & THE DRIVE AXLE MADE THEREWITH,” andfiled on Jun. 15, 2018. The entire contents of each of the above-listedapplications are hereby incorporated by reference for all purposes.

FIELD

The presently disclosed subject matter relates to an axle assembly, andmore particularly to a multi-speed gearbox with high torque ratio for anaxle assembly.

BACKGROUND

The present disclosure relates to gearboxes and electric drive axles.Electric and hybrid-electric vehicles utilize an electric power sourcein communication with an electric motor to provide drive, or augmenteddrive, to the vehicle. Electric vehicles have several characteristicssuperior to conventional internal combustion engine driven vehicles. Forexample, electric motors produce fewer vibrations than internalcombustion engines, and electric motors achieve maximum torque morequickly than internal combustion engines.

However, in order for the conventional electric vehicle to achievesufficient speed, the electric motor must allow for reasonable powerover a broad speed range. An electric motor which can provide reasonablepower over a broad speed range is typically large and heavy.

In view of the above, it would be desirable to produce an axle assemblycapable of operating at high torque and low speed while having reducedsize, weight, and production costs.

SUMMARY

In concordance and agreement with the present disclosure, an axleassembly capable of operating at high torque and low speed while havingreduced size, weight, and production costs, has surprisingly beendiscovered.

In one embodiment, an axle assembly, comprises: an electric motor havingan output shaft; at least one of a gear and a first planetary gearassembly coupled to the output shaft; a differential mechanism connectedwith the at least one of the gear and the first planetary gear assembly,wherein the differential mechanism is coupled to at least one axleshaft; a first clutch assembly drivingly connected with at least one ofthe output shaft and the differential mechanism, wherein an engagementof the first clutch assembly produces a first speed ratio; and a secondclutch assembly drivingly connected with at least one of the outputshaft and the differential mechanism, wherein an engagement of thesecond clutch assembly produces a second speed ratio.

As aspects of certain embodiments, the axle assembly further comprises athird clutch assembly drivingly connected with at least one of theoutput shaft and the differential mechanism, wherein an engagement ofthe third clutch assembly produces a third speed ratio.

As aspects of certain embodiments, the axle assembly further comprises acompound idler assembly connected to at least one of the output shaftand the differential mechanism.

As aspects of certain embodiments, the compound idler assembly isdisposed offset and parallel to the output shaft of the electric motor.

As aspects of certain embodiments, at least one of the first planetarygear assembly, the first clutch assembly, and the second clutch assemblyis disposed on the compound idler assembly.

As aspects of certain embodiments, one of the first clutch assembly, thesecond clutch assembly, and the third clutch assembly is coupled to thefirst planetary gear assembly.

As aspects of certain embodiments, the at least one axle shaft iscoaxially aligned with the output shaft.

As aspects of certain embodiments, the first planetary gear assembly isselectively coupled to the output shaft by one of the first clutchassembly and the second clutch assembly.

As aspects of certain embodiments, the axle assembly further comprises asecond planetary gear assembly coupled to the output shaft.

As aspects of certain embodiments, the second planetary gear assembly isselectively coupled to the output shaft by one of the first clutchassembly and the second clutch assembly.

As aspects of certain embodiments, the second planetary gear assembly iscoupled to the first planetary gear assembly.

As aspects of certain embodiments, the axle assembly further comprises athird planetary gear assembly coupled to the at least one axle shaft.

As aspects of certain embodiments, the axle assembly further comprises afourth planetary gear assembly coupled to the at least one axle shaft.

In another embodiment, a method for an axle assembly, comprises:providing an axle assembly including: an electric motor having an outputshaft; at least one of a gear and a first planetary gear assemblycoupled to the output shaft; a differential mechanism connected with theat least one of the gear and the first planetary gear assembly, whereinthe differential mechanism is coupled to at least one axle shaft; afirst clutch assembly drivingly connected with at least one of theoutput shaft and the differential mechanism, wherein an engagement ofthe first clutch assembly produces a first speed ratio; and a secondclutch assembly drivingly connected with at least one of the outputshaft and the differential mechanism, wherein an engagement of thesecond clutch assembly produces a second speed ratio; and causing theengagement of one of the first clutch assembly and the second clutchassembly.

As aspects of certain embodiments, the engagement of the first clutchassembly produces a first speed ratio and engagement of the secondclutch assembly produces a second speed ratio.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are incorporated herein as part of thespecification. The drawings described herein illustrate embodiments ofthe presently disclosed subject matter, and are illustrative of selectedprinciples and teachings of the present disclosure. However, thedrawings do not illustrate all possible implementations of the presentlydisclosed subject matter, and are not intended to limit the scope of thepresent disclosure in any way.

FIG. 1 is a schematic diagram of a vehicle driveline according to anembodiment of the presently disclosed subject matter;

FIG. 2 is a schematic diagram of an electric axle assembly according toan embodiment of the presently disclosed subject matter;

FIG. 3 is a schematic diagram of an electric axle assembly according toanother embodiment of the presently disclosed subject matter;

FIG. 4 is a schematic diagram of an electric axle assembly according toanother embodiment of the presently disclosed subject matter;

FIG. 5 is a schematic diagram of an electric axle assembly according toanother embodiment of the presently disclosed subject matter;

FIG. 6 is a schematic diagram of an electric axle assembly according toanother embodiment of the presently disclosed subject matter;

FIG. 7 is a schematic diagram of an electric axle assembly according toanother embodiment of the presently disclosed subject matter; and

FIG. 8 is a schematic diagram of an electric axle assembly according toanother embodiment of the presently disclosed subject matter.

DETAILED DESCRIPTION

It is to be understood that the presently disclosed subject matter mayassume various alternative orientations and step sequences, except whereexpressly specified to the contrary. It is also to be understood thatthe specific assemblies and systems illustrated in the attacheddrawings, and described in the following specification are simplyexemplary embodiments of the inventive concepts defined herein. Hence,specific dimensions, directions or other physical characteristicsrelating to the embodiments disclosed are not to be considered aslimiting, unless expressly stated otherwise. Also, although they may notbe, like elements in various embodiments described herein may becommonly referred to with like reference numerals within this section ofthe application.

Embodiments of an electric drive axle assembly 100, 200, 300, 400, 500,600, 700 are described below. In certain embodiments, one of theelectric drive axle assemblies 100, 200, 300, 400, 500, 600, 700 isutilized with a pure electric vehicle (not depicted) where the one ofthe electric drive axle assemblies 100, 200, 300, 400, 500, 600, 700 isthe only driving axle. In other embodiments, as illustrated in FIG. 1,the one of the electric drive axle assemblies 100, 200, 300, 400, 500,600, 700 is utilized with a hybrid all-wheel-drive vehicle 10, where thefront axle is driven by an internal combustion engine 12, and the rearaxle is the one of the electric drive axle assemblies 100, 200, 300,400, 500, 600, 700. In still other embodiments, the one of the electricdrive axle assemblies 100, 200, 300, 400, 500, 600, 700 is utilized in ahybrid commercial vehicle (not depicted) comprising a tandem axle inwhich the front tandem axle is driven by an internal combustion engine,and the rear tandem axle is the one of the electric drive axleassemblies 100, 200, 300, 400, 500, 600, 700 (or vice versa). Theelectric drive axle assemblies 100, 200, 300, 400, 500, 600, 700 mayhave applications in commercial vehicles, both light duty and heavy-dutyvehicles, and for passenger, off-highway, and sport utility vehicles.Additionally, the electric drive axle assemblies 100, 200, 300, 400,500, 600, 700 described herein may be adapted for use in front and/orrear driving axles, and in steerable and non-steerable axles. It wouldbe understood by one of ordinary skill in the art that the electricdrive axle assemblies 100, 200, 300, 400, 500, 600, 700 also haveindustrial, locomotive, military, agricultural, and aerospaceapplications.

As illustrated in FIGS. 2-9, each of the electric drive axle assemblies100, 200, 300, 400, 500, 600, 700 may include an integrated drivesystem. The electric drive axle assemblies 100, 200, 300, 400, 500, 600,700 each may include a respective electric motor 104, 204, 304, 404,504, 604, 704 coupled with a power source (not depicted). The electricmotors 104, 204, 304, 404, 504, 604, 704 may be a permanent magnetsynchronous machine comprising a stator (not depicted) disposedconcentrically about a rotor (not depicted). The electric drive axleassemblies 100, 200, 300, 400, 500, 600, 700 may additionally comprisean inverter (not depicted) for converting direct current to alternatingcurrent when the electric motors 104, 204, 304, 404, 504, 604, 704 areutilized to drive the vehicle, and for converting alternating current todirect current when the vehicle 10 decelerates. Each of the electricmotors 104, 204, 304, 404, 504, 604, 704 may be referred to herein as amotor-generator. Further, the electric drive axle assemblies 100, 200,300, 400, 500, 600, 700 may include cooling fluid (not depicted) suchas, but not limited to, automatic transmission fluid or axle oilintegrated with the lubricant of the electric drive axle assemblies 100,200, 300, 400, 500, 600, 700 for cooling the electric motors 104, 204,304, 404, 504, 604, 704 and the inverter. In another embodiment (notdepicted), the cooling fluid for the electric motors 104, 204, 304, 404,504, 604, 704 and the inverter may not be integrated with the axle oil.

In the embodiment shown in FIG. 2, an output shaft 106 is coupled withthe rotor of the electric motor 104 for rotation therewith. A first gear108 is coupled with the output shaft 106 for rotation therewith. Theoutput shaft 106 may be rotatably supported via first and second rollerbearings 110A, 110B. In an embodiment, the first gear 108 is forged onthe output shaft 106. In another embodiment, the first gear 108 may bewelded to the output shaft 106. In still another embodiment, the firstgear 108 may be splined to the output shaft 106. The electric motor 104drives a compound idler assembly 112 via the output shaft 106 and thefirst gear 108.

As illustrated, the output shaft 106, the compound idler assembly 112,and axle shafts 16, 18 of the electric drive axle assembly 100 aredisposed offset and parallel relative to one another. In an embodiment,the compound idler assembly 112 comprises an idler shaft 114. It shouldbe appreciated that the idler shaft 114 may be rotatably supported in anaxle housing 14, shown in FIG. 1, via third and fourth roller bearings116A, 116B. A second gear 118 is disposed concentrically about at leasta portion of the idler shaft 114. The second gear 118 is in meshedengagement with the first gear 108 and receives torque therefrom whenthe electric motor 104 outputs torque to the output shaft 106. In anembodiment, the second gear 118 has a generally cylindrical shape. Thesecond gear 118 is part of a first clutch assembly 125.

In an embodiment, the first clutch assembly 125 comprises a first clutchdrum 126 disposed at least partially concentrically within the secondgear 118. A radially outer surface of the first clutch drum 126 iscoupled with a radially inner surface of the second gear 118. In anembodiment, the first clutch drum 126 and the second gear 118 may becoupled via splined engagement. In another embodiment, the first clutchdrum 126 and the second gear 118 may be coupled via an interference fit.In yet another embodiment, the second gear 118 and the first clutch drum126 may comprise a unitary component. The first clutch drum 126 may berotatably supported on the idler shaft 114 via a fifth roller bearing129. A first rotary sealing member 131 is disposed adjacent to the fifthroller bearing 129 to create a substantially fluid-tight seal between aportion of the first clutch drum 126 and a portion of the idler shaft114.

A first clutch hub 128 is disposed at least partially concentricallywithin the first clutch drum 126. In an embodiment, the first clutch hub128 may be coupled for rotation with the idler shaft 114. In anotherembodiment, the first clutch hub 128 may comprise a splined radiallyinner surface in meshed engagement with complimentary splines on theidler shaft 114. The second gear 118 is entirely supported on the idlershaft 114 by the first clutch hub 128 via the first clutch drum 126. Inanother embodiment, the first clutch hub 128 may be formed unitary andintegral with the idler shaft 114.

A first plurality of clutch plates 134 are coupled for rotation with thefirst clutch drum 126. The clutch plates 134 receive torque from thefirst clutch drum 126 and may move axially within the first clutch drum126. A second plurality of clutch plates 136 are in meshed engagementwith the first clutch hub 128. The second plurality of clutch plates 136are interleaved with the first plurality of clutch plates 134. Thesecond plurality of clutch plates 136 may move axially along the firstclutch hub 128. The first clutch assembly 125 may be nested within thesecond gear 118.

A third gear 138 is disposed concentrically about the idler shaft 114.The third gear 138 is coupled with the second gear 118 for rotationtherewith. In an embodiment, the third gear 138 may be coupled with thesecond gear 118 via a hollow cylindrical shaft 139. A second rotarysealing member 141 may be disposed radially between the hollowcylindrical shaft 139 and the idler shaft 114. A sixth roller bearing143 may be disposed axially adjacent to the second rotary sealing member141 to at least partially rotatably support the third and fourth gears118, 138 on the idler shaft 114. In certain embodiments, the secondrotary sealing member 141 is disposed adjacent to the sixth rollerbearing 143 to create a substantially fluid-tight seal between a portionof the first clutch drum 126 and a portion of the idler shaft 114.

In an embodiment, as illustrated in FIG. 2, the third gear 138 may be asun gear of a planetary gear assembly 140. The planetary gear assembly140 may further comprise two or more planet gears 142 in meshedengagement with the third gear 138. The planet gears 142 may berotatably disposed on planet pins (not depicted) coupled with a planetcarrier 144. The planet carrier 144 may be coupled with the idler shaft114 for rotation therewith. The planet gears 142 may also be in meshedengagement with a ring gear 146 disposed at least partiallyconcentrically about the planet gears 142 and the third gear 138. Thering gear 146 may be selectively engaged with a stationary structuresuch as the axle housing 14, for example, via a second clutch assembly150.

The second clutch assembly 150 may comprise a second clutch hub 152coupled with the ring gear 146. The second clutch hub 152 may include aplurality of axially extending splines on a radially outer surfacethereof. A first plurality of clutch plates 154 are in meshed engagementwith the second clutch hub 152. The first plurality of clutch plates 154may move axially along the second clutch hub 152. The stationarystructure may comprise a second clutch drum 156 having a plurality ofaxially extending splines on a radially inner surface thereof. A secondplurality of clutch plates 158 are in meshed engagement with the secondclutch drum 156. The second plurality of clutch plates 158 may moveaxially within the second clutch drum 156 and are interleaved with thefirst plurality of clutch plates 154.

A fourth gear 160 is disposed concentrically about the idler shaft 114axially between the planet carrier 144 and the fourth roller bearing116B. The fourth gear 160 may be coupled for rotation with the idlershaft 114. A first actuator assembly 162 may be utilized to selectivelyactuate the first clutch assembly 125. In an embodiment, as illustratedin FIG. 2, the first actuator assembly 162 may comprise a hydraulicactuator. In an embodiment, the first actuator assembly 162 comprises ahollow portion 164 of the idler shaft 114. The idler shaft hollowportion 164 may comprise one more radially extending apertures 166 influid communication with a chamber 168. The chamber 168 may be definedby the idler shaft 114, a portion of the first clutch drum 126, therotary sealing member 131, and a pressure plate 170. The first actuatorassembly 162 may comprise a fluid reservoir (not depicted) in fluidcommunication with the hollow portion 164 of the idler shaft 114. Thehollow portion 164 of the idler shaft 114 is in fluid communication withthe chamber 168 of the first actuator assembly 162 via the one or moreapertures 166. When the fluid pressure in the chamber 168 is increasedvia a pump (not depicted), the pressure plate 170 is axially actuated tofrictionally engage the first and second pluralities of clutch plates134, 136 of the first clutch assembly 125.

The fourth gear 160 is in meshed engagement with a fifth gear 172. Thefifth gear 172 is coupled with, and fixed for rotation with, adifferential case 174. The differential case 174 is part of adifferential mechanism 176. The differential case 174 may be rotatablysupported within the axle housing 14 via seventh and eighth rollerbearings 178, 180. The differential mechanism 176 further includes twoor more differential pinions 182. The differential pinions 182 arecoupled within the differential case 174 via a pinion shaft (i.e.,spider shaft) (not depicted). In an embodiment, the pinion shaft maycomprise a cross member. The differential pinions 182 are in meshedengagement with a first side gear 184 and a second side gear 186. Thefirst side gear 184 is coupled for rotation with the first axle shaft16, and the second side gear 186 is coupled for rotation with the secondaxle shaft 18. A second actuator assembly (not depicted) may be utilizedto actuate and selectively engage the second clutch assembly 150. Thesecond actuator assembly may comprise, but is not limited to, ahydraulic actuator, an electromagnetic actuator, a cam actuator, or aball and ramp actuator.

The high speed of electric motors presents obstacles to their use withconventional transmission gearbox designs. To prevent operating bearingsdisposed between a rotating clutch assembly and an actuator assembly atthe high speeds produced by an electric motor, the compound idlerassembly 112 locates the first and second clutch assemblies 125, 150after a first gear reduction comprising the first gear 108 and thesecond gear 118.

In operation, when a first speed ratio is desired, the first actuatorassembly 162 causes the first clutch assembly 125 to engage, while thesecond clutch assembly 150 remains disengaged. When the first clutchassembly 125 is engaged, the output shaft 106 of the electric motor 104causes the output shaft 106 and the first gear 108 coupled thereto, torotate therewith. Torque is transferred from the electric motor 104 tothe first gear 108. A rotation of the first gear 108 drives the secondgear 118 of the compound idler assembly 112. Hence, the torque is thentransferred from the first gear 108 to the second gear 118. Since thefirst clutch assembly 125 is engaged, the rotation of the second gear118 causes the idler shaft 114 and the fourth gear 160 coupled thereto,to rotate therewith. The torque from the second gear 118 is thentransferred to the idler shaft 114 via the first clutch assembly 125,and from the idler shaft 114 to the fourth gear 160. The torquetransferred from the second gear 118 to the fourth gear 160 remainsunchanged because the planetary gear assembly 140 freely rotates due tothe second clutch assembly 150 being disengaged.

A rotation of the fourth gear 160 drives the fifth gear 172 of thedifferential mechanism 176, and causes the differential case 174 torotate therewith. As such, the torque from the fourth gear 160 istransferred through the fifth gear 172 to the differential mechanism176. A rotation of the differential case 174 further causes the firstand second axle shafts 16, 18 to rotate therewith. The rotation of thedifferential mechanism 176 transfers a desired first torque from thedifferential mechanism 176 to the first and second axle shafts 16, 18.When the electric drive axle 100 is in a power generation mode, thetorque transfer described above is reversed.

In certain embodiments, the first speed ratio may also be referred to asa highway ratio. The first speed ratio enables the electric drive axleassembly 100 to operate at low torque and high speed.

When a second speed ratio is desired, the first clutch assembly 125 isdisengaged, while the second actuator assembly causes the second clutchassembly 150 to engage. When the second clutch assembly 150 is engaged,the output shaft 106 of the electric motor 104 causes the output shaft106 and the first gear 108 coupled thereto, to rotate therewith. Torqueis transferred from the electric motor 104 to the first gear 108. Arotation of the first gear 108 drives the second gear 118 of thecompound idler assembly 112. Hence, the torque is transferred from thefirst gear 108 to the second gear 118. Since the second gear 118 and thethird gear 138 are disposed on the cylindrical shaft 139 and the secondclutch assembly 150 is engaged, a rotation of the second gear 118 causesthe cylindrical shaft 139 and the third gear 138 coupled thereto, torotate therewith. The torque is then transferred from the first gear 108to the third gear 138 via the second gear 118. Since the second clutchassembly 150 is engaged, a rotation of the third gear 138 drives theplanet gears 142 and the planet carrier 144 coupled thereto. As such,the torque from the third gear 138 is then transferred to the planetcarrier 144 via the planet gears 142. A rotation of the planet carrier144 causes the idler shaft 114 and the fourth gear 160 coupled thereto,to rotate therewith. The torque from the planet carrier 144 is thentransferred to the idler shaft 114 to the fourth gear 160. The torquetransferred from the second gear 118 to the fourth gear 160 is increasedbecause of the planetary gear assembly 140.

A rotation of the fourth gear 160 drives the fifth gear 172 of thedifferential mechanism 176, and causes the differential case 174 torotate therewith. As such, the torque from the fourth gear 160 istransferred through the fifth gear 172 to the differential mechanism176. A rotation of the differential case 174 further causes the firstand second axle shafts 16, 18 to rotate therewith. The rotation of thedifferential mechanism 176 transfers a desired second torque from thedifferential mechanism 176 to the first and second axle shafts 16, 18.When the electric drive axle 100 is in a power generation mode, thetorque transfer described above is reversed.

In certain embodiments, the second speed ratio may also be referred toas a crawl ratio. The second speed ratio enables the electric drive axleassembly 100 to operate at high torque and low speed.

Accordingly, the compound idler assembly 112 enables the electric driveaxle assembly 100 to achieve a drive ratio span facilitating urban,rural, and highway driving as well as towing and rock crawling.

As illustrated in FIG. 3, in an embodiment, the electric drive axleassembly 200 includes an output shaft 206. The output shaft 206 iscoupled with the rotor of the electric motor 204 for rotation therewith.A first gear 208 is coupled with the output shaft 206 for rotationtherewith. The output shaft 206 may be rotatably supported via first andsecond roller bearings 210A, 210B. In an embodiment, the first gear 208is forged on the output shaft 206. In another embodiment, the first gear208 may be welded to the output shaft 206. In still another embodiment,the first gear 208 may be splined to the output shaft 206. The electricmotor 204 drives a compound idler assembly 212 via the output shaft 206and the first gear 208.

As illustrated, the output shaft 206 is disposed coaxially with the axleshafts 16, 18, and the compound idler assembly 212 is disposed offsetand parallel to the output shaft 206. In an embodiment, the compoundidler assembly 212 comprises an idler shaft 214. It should beappreciated that the idler shaft 214 may be rotatably supported in theaxle housing 14, shown in FIG. 1, via third and fourth roller bearings216A, 216B. The second gear 218 is disposed concentrically about atleast a portion of the idler shaft 214. In an embodiment, the secondgear 218 has a generally cylindrical shape. The second gear 218 is partof a first clutch assembly 225.

In an embodiment, the first clutch assembly 225 comprises a first clutchdrum 226 disposed at least partially concentrically within the secondgear 218. A radially outer surface of the first clutch drum 226 iscoupled with a radially inner surface of the second gear 218. In anembodiment, the first clutch drum 226 and the second gear 218 may becoupled via splined engagement. In another embodiment, the first clutchdrum 226 and the second gear 218 may be coupled via an interference fit.In yet another embodiment, the second gear 218 and the first clutch drum226 may comprise a unitary component. The first clutch drum 226 may berotatably supported on the idler shaft 214 via a fifth roller bearing229. A first rotary sealing member 231 is disposed adjacent to the fifthroller bearing 229 to create a substantially fluid-tight seal between aportion of the first clutch drum 226 and a portion of the idler shaft214.

A first clutch hub 228 is disposed at least partially concentricallywithin the first clutch drum 226. In an embodiment, the first clutch hub228 may be coupled for rotation with the idler shaft 214. In anotherembodiment, the first clutch hub 228 may comprise a splined radiallyinner surface in meshed engagement with complimentary splines on theidler shaft 214. The second gear 218 is entirely supported on the idlershaft 214 by the first clutch hub 228 via the first clutch drum 226. Inanother embodiment, the first clutch hub 228 may be formed unitary andintegral with the idler shaft 214.

A first plurality of clutch plates 234 are coupled for rotation with thefirst clutch drum 226. The clutch plates 234 receive torque from thefirst clutch drum 226 and may move axially within the first clutch drum226. A second plurality of clutch plates 236 are in meshed engagementwith the first clutch hub 228. The second plurality of clutch plates 236are interleaved with the first plurality of clutch plates 234. Thesecond plurality of clutch plates 236 may move axially along the firstclutch hub 228. The first clutch assembly 225 may be nested within thesecond gear 218.

A third gear 238 is disposed concentrically about the idler shaft 214.The third gear 238 is coupled with the second gear 218 for rotationtherewith. In an embodiment, the third gear 238 may be coupled with thesecond gear 218 via a hollow cylindrical shaft 239. A second rotarysealing member 241 may be disposed radially between the hollowcylindrical shaft 239 and the idler shaft 214. A sixth roller bearing243 may be disposed axially adjacent to the second rotary sealing member241 to at least partially rotatably support the third and fourth gears218, 238 on the idler shaft 214. In certain embodiments, the secondrotary sealing member 241 is disposed adjacent to the sixth rollerbearing 243 to create a substantially fluid-tight seal between a portionof the first clutch drum 226 and a portion of the idler shaft 214.

In an embodiment, as illustrated in FIG. 3, the third gear 238 may be asun gear of a planetary gear assembly 240. The planetary gear assembly240 may further comprise two or more planet gears 242 in meshedengagement with the third gear 238. The planet gears 242 may berotatably disposed on planet pins (not depicted) coupled with a planetcarrier 244. The planet carrier 244 may be coupled with the idler shaft214 for rotation therewith. The planet gears 242 may also be in meshedengagement with a ring gear 246 disposed at least partiallyconcentrically about the planet gears 242 and the third gear 238. Thering gear 246 may be selectively engaged with a stationary structuresuch as the axle housing 14, for example, via a second clutch assembly250.

The second clutch assembly 250 may comprise a second clutch hub 252coupled with the ring gear 246. The second clutch hub 252 may include aplurality of axially extending splines on a radially outer surfacethereof. A first plurality of clutch plates 254 are in meshed engagementwith the second clutch hub 252. The first plurality of clutch plates 254may move axially along the second clutch hub 252. The stationarystructure may comprise a second clutch drum 256 having a plurality ofaxially extending splines on a radially inner surface thereof. A secondplurality of clutch plates 258 are in meshed engagement with the secondclutch drum 256. The second plurality of clutch plates 258 may moveaxially within the second clutch drum 256 and are interleaved with thefirst plurality of clutch plates 254.

A fourth gear 260 is disposed concentrically about the idler shaft 214axially between the planet carrier 244 and the fourth roller bearing216B. The fourth gear 260 may be coupled for rotation with the idlershaft 214. A first actuator assembly 262 may be utilized to selectivelyactuate the first clutch assembly 225. In an embodiment, as illustratedin FIG. 3, the first actuator assembly 262 may comprise a hydraulicactuator. In an embodiment, the first actuator assembly 262 comprises ahollow portion 264 of the idler shaft 214. The idler shaft hollowportion 264 may comprise one more radially extending apertures 266 influid communication with a chamber 268. The chamber 268 may be definedby the idler shaft 214, a portion of the first clutch drum 226, therotary sealing member 231, and a pressure plate 270. The first actuatorassembly 262 may comprise a fluid reservoir (not depicted) in fluidcommunication with the hollow portion 264 of the idler shaft 214. Thehollow portion 264 of the idler shaft 214 is in fluid communication withthe chamber 268 of the first actuator assembly 262 via the one or moreapertures 266. When the fluid pressure in the chamber 268 is increasedvia a pump (not depicted), the pressure plate 270 is axially actuated tofrictionally engage the first and second pluralities of clutch plates234, 236 of the first clutch assembly 225.

The fourth gear 260 is in meshed engagement with a fifth gear 272. Thefifth gear 272 is coupled with, and fixed for rotation with, adifferential case 274. The differential case 274 is part of adifferential mechanism 276. The differential case 274 may be rotatablysupported within the axle housing 14 via seventh and eighth rollerbearings 278, 280. The differential mechanism 276 further includes twoor more differential pinions 282. The differential pinions 282 arecoupled within the differential case 274 via a pinion shaft (i.e.,spider shaft) (not depicted). In an embodiment, the pinion shaft maycomprise a cross member. The differential pinions 282 are in meshedengagement with a first side gear 284 and a second side gear 286. Thefirst side gear 284 is coupled for rotation with the first axle shaft16, and the second side gear 286 is coupled for rotation with the secondaxle shaft 18. A second actuator assembly (not depicted) may be utilizedto actuate and selectively engage the second clutch assembly 250. Thesecond actuator assembly may comprise, but is not limited to, ahydraulic actuator, an electromagnetic actuator, a cam actuator, or aball and ramp actuator.

The electric drive axle assembly 200 further includes a sixth gear 213in meshed engagement with the first gear 208 and the second gear 218.The sixth gear 213 receives torque from the first gear 208 and transmitstorque to the second gear 218 when the electric motor 204 outputs torqueto the output shaft 206.

In operation, when a first speed ratio is desired, the first actuatorassembly 262 causes the first clutch assembly 225 to engage, while thesecond clutch assembly 250 remains disengaged. When the first clutchassembly 225 is engaged, the output shaft 206 of the electric motor 204causes the output shaft 206 and the first gear 208 coupled thereto, torotate therewith. Torque is transferred from the electric motor 204 tothe first gear 208. A rotation of the first gear 208 drives the sixthgear 213, and thereby the second gear 218 of the compound idler assembly212. Hence, the torque is then transferred from the first gear 208 tothe second gear 218 via the sixth gear 213. Since the first clutchassembly 225 is engaged, the rotation of the second gear 218 causes theidler shaft 214 and the fourth gear 260 coupled thereto, to rotatetherewith. The torque from the second gear 218 is then transferred tothe idler shaft 214 via the first clutch assembly 225, and from theidler shaft 214 to the fourth gear 260. The torque transferred from thesecond gear 218 to the fourth gear 260 remains unchanged because theplanetary gear assembly 240 freely rotates due to the second clutchassembly 250 being disengaged.

A rotation of the fourth gear 260 drives the fifth gear 272 of thedifferential mechanism 276, and causes the differential case 274 torotate therewith. As such, the torque from the fourth gear 260 istransferred through the fifth gear 272 to the differential mechanism276. A rotation of the differential case 274 further causes the firstand second axle shafts 16, 18 to rotate therewith. The rotation of thedifferential mechanism 276 transfers a desired first torque from thedifferential mechanism 276 to the first and second axle shafts 16, 18.When the electric drive axle 200 is in a power generation mode, thetorque transfer described above is reversed.

In certain embodiments, the first speed ratio may also be referred to asa highway ratio. The first speed ratio enables the electric drive axleassembly 200 to operate at low torque and high speed.

When a second speed ratio is desired, the first clutch assembly 225 isdisengaged, while the second actuator assembly causes the second clutchassembly 250 to engage. When the second clutch assembly 250 is engaged,the output shaft 206 of the electric motor 204 causes the output shaft206 and the first gear 208 coupled thereto, to rotate therewith. Torqueis transferred from the electric motor 204 to the first gear 208. Arotation of the first gear 208 drives the sixth gear 213, and therebythe second gear 218 of the compound idler assembly 212. Hence, thetorque is transferred from the first gear 208 to the second gear 218 viathe sixth gear 213. Since the second gear 218 and the third gear 238 aredisposed on the cylindrical shaft 239 and the second clutch assembly 250is engaged, a rotation of the second gear 218 causes the cylindricalshaft 239 and the third gear 238 coupled thereto, to rotate therewith.The torque is then transferred from the first gear 208 to the third gear238 via the second gear 218. Since the second clutch assembly 250 isengaged, a rotation of the third gear 238 drives the planet gears 242and the planet carrier 244 coupled thereto. As such, the torque from thethird gear 238 is then transferred to the planet carrier 244 via theplanet gears 242. A rotation of the planet carrier 244 causes the idlershaft 214 and the fourth gear 260 coupled thereto, to rotate therewith.The torque from the planet carrier 244 is then transferred to the idlershaft 214 to the fourth gear 260. The torque transferred from the secondgear 218 to the fourth gear 260 is increased because of the planetarygear assembly 240.

A rotation of the fourth gear 260 drives the fifth gear 272 of thedifferential mechanism 276, and causes the differential case 274 torotate therewith. As such, the torque from the fourth gear 260 istransferred through the fifth gear 272 to the differential mechanism276. A rotation of the differential case 274 further causes the firstand second axle shafts 16, 18 to rotate therewith. The rotation of thedifferential mechanism 276 transfers a desired second torque from thedifferential mechanism 276 to the first and second axle shafts 16, 18.When the electric drive axle 200 is in a power generation mode, thetorque transfer described above is reversed.

In certain embodiments, the second speed ratio may also be referred toas a crawl ratio. The second speed ratio enables the electric drive axleassembly 200 to operate at high torque and low speed.

Accordingly, the compound idler assembly 212 enables the electric driveaxle assembly 200 to achieve a drive ratio span facilitating urban,rural, and highway driving as well as towing and rock crawling.

The high speed of electric motors presents obstacles to their use withconventional transmission gearbox designs. To prevent operating bearingsdisposed between a rotating clutch assembly and an actuator assembly atthe high speeds produced by an electric motor, the compound idlerassembly 212 locates the first and second clutch assemblies 225, 250after a first gear reduction comprising the first gear 208 and thesecond gear 218.

Now referring to an embodiment shown in FIG. 4, the electric drive axleassembly 300 comprises an output shaft 306, axle shafts 16, 18, and acompound idler assembly 307 disposed offset and parallel to the motoroutput shaft relative to each other. In an embodiment, the electricdrive axle 300 comprises the output shaft 306 coupled with the rotor ofthe electric motor 304 for rotation therewith. A first gear 308 may becoupled with the output shaft 306 and fixed for rotation therewith. Inan embodiment, the first gear 308 is forged on the output shaft 306. Inanother embodiment, the first gear 308 may be welded to the output shaft306. In still another embodiment, the first gear 308 may be splined tothe output shaft 306. The first gear 308 may be a sun gear of aplanetary gear assembly 309. The planetary gear assembly 309 may furthercomprise two or more planet gears 312 in meshed engagement with thefirst gear 308. The planet gears 312 may be rotatably disposed on planetpins (not depicted) coupled with a planet carrier 314. The planetcarrier 314 may be coupled with a second shaft 316 and fixed forrotation therewith. The planet gears 312 may also be in meshedengagement with a ring gear 318 disposed at least partiallyconcentrically about the planet gears 312 and the first gear 308. Thering gear 318 may be coupled with a stationary structure such as theaxle housing 14, for example, and fixed thereto.

The second shaft 316 may be disposed coaxially with the output shaft 306and may be rotatably supported in the axle housing 14 via first andsecond bearings 320A, 320B. A second gear 322 is coupled with the secondshaft 316 and fixed for rotation therewith. The second gear 322 is inmeshed engagement with a third gear 324. The third gear 324 is coupledwith a first clutch drum 328 of a first clutch assembly 326. In certainembodiments, the compound idler assembly 307 includes the first clutchassembly 326. It is understood that the compound idler assembly 307 maybe rotatably supported in the axle housing 14 via third and fourthbearings 327A, 327B

Additionally, the first clutch drum 328 disposed at least partiallyconcentrically within the third gear 324. A radially outer surface ofthe first clutch drum 328 is coupled with a radially inner surface ofthe third gear 324. In an embodiment, the first clutch drum 328 and thethird gear 324 may be coupled via splined engagement. In anotherembodiment, the first clutch drum 328 and the third gear 324 may becoupled via an interference fit. In yet another embodiment, the thirdgear 324 and the first clutch drum 328 may comprise a unitary component.The first clutch drum 328 is rotatably supported on a third shaft 330via fifth and sixth bearings 332A, 332B. Further, rotary sealing members334A, 334B are disposed adjacent to the roller bearings 332A, 332B,respectively, to create a substantially fluid-tight seal between aportion of the first clutch drum 328 and a first portion 336 of thethird shaft 330. The third gear 324 is entirely supported on the firstportion 336 by the first clutch drum 328.

A first clutch hub 338 is disposed at least partially concentricallywithin the first clutch drum 328. In an embodiment, the first clutch hub338 may be coupled for rotation with a first portion 336 of the thirdshaft 330. In an embodiment, the first clutch hub 338 may comprise asplined radially inner surface in meshed engagement with complimentarysplines on the first portion 336 of the third shaft 330. In anotherembodiment, the first clutch hub 338 may be formed unitary and integralwith the first portion 336 of the third shaft 330.

A first plurality of clutch plates 340 are coupled for rotation with thefirst clutch drum 328. The clutch plates 340 receive torque from thefirst clutch drum 328 and may move axially within the first clutch drum328. A second plurality of clutch plates 342 are in meshed engagementwith the first clutch hub 338. The second plurality of clutch plates 342are interleaved with the first plurality of clutch plates 340. Thesecond plurality of clutch plates 342 may move axially on the firstclutch hub 338. The first clutch assembly 326 may be nested entirelywithin the third gear 324.

A first actuator assembly 344 may be utilized to selectively actuate thefirst clutch assembly 326. In an embodiment, as illustrated in FIG. 4,the first actuator assembly 344 may comprise a hydraulic actuator. In anembodiment, the first actuator assembly 344 comprises the first portion336 of the third shaft 330. In an embodiment, the first portion 336 mayhave a generally cylindrical shape defining a fluid conduit 346. Thefirst portion 336 may also comprise one more radially extendingapertures 348 in fluid communication with both the fluid conduit 346 anda chamber 350. The chamber 350 may be defined by the first portion 336,a portion of the first clutch drum 328, the rotary sealing members 334A,334B, and a pressure plate 352. The first actuator assembly 344 may alsocomprise a fluid reservoir (not depicted) in fluid communication withthe fluid conduit 346. The fluid conduit 346 is in fluid communicationwith the chamber 350 via the one or more apertures 348. When the fluidpressure in the chamber 350 is increased via a pump (not depicted), thepressure plate 352 is axially actuated to frictionally engage the firstand second pluralities of clutch plates 340, 342 of the first clutchassembly 326.

A fourth gear 354 is coupled with the second shaft 316 and fixed forrotation therewith. The fourth gear 354 is in meshed engagement with afifth gear 356. The fifth gear 356 is coupled with a second clutch drum360 of a second clutch assembly 358. In an embodiment, the second clutchassembly 358 comprises substantially the same components as the firstclutch assembly 326 and is operated in substantially the same manner.

The second clutch drum 360 is disposed at least partially concentricallywithin the fifth gear 356. A radially outer surface of the second clutchdrum 360 is coupled with a radially inner surface of the fifth gear 356.In an embodiment, the second clutch drum 360 and the fifth gear 356 maybe coupled via splined engagement. In another embodiment, the secondclutch drum 360 and the fifth gear 356 may be coupled via aninterference fit. In yet another embodiment, the fifth gear 356 and thesecond clutch drum 360 may comprise a unitary component. The secondclutch drum 360 is rotatably supported on the third shaft 330 viaseventh and eighth bearings 332C, 332D. Further, rotary sealing members334C, 334D are disposed adjacent to the bearings 332C, 332D,respectively, to create a substantially fluid-tight seal between aportion of the second clutch drum 360 and a second portion 362 of thethird shaft 330. The fifth gear 356 is entirely supported on the secondportion 362 by the second clutch drum 360.

A second clutch hub 368 is disposed at least partially concentricallywithin the second clutch drum 360. In an embodiment, the second clutchhub 368 may be coupled for rotation with a second portion 362 of thethird shaft 330. In an embodiment, the second clutch hub 368 maycomprise a splined radially inner surface in meshed engagement withcomplimentary splines on the second portion 362. In another embodiment,the second clutch hub 368 may be formed unitary and integral with thesecond portion 362 of the third shaft 330.

A first plurality of clutch plates 370 are coupled for rotation with thesecond clutch drum 360. The clutch plates 370 receive torque from thesecond clutch drum 360 and may move axially within the second clutchdrum 360. A second plurality of clutch plates 372 are in meshedengagement with the second clutch hub 368. The second plurality ofclutch plates 372 are interleaved with the first plurality of clutchplates 370. The second plurality of clutch plates 372 may move axiallyon the second clutch hub 368. The second clutch assembly 358 may benested entirely within the fifth gear 356.

A second actuator assembly 374 may be utilized to selectively actuatethe second clutch assembly 358. In an embodiment, as illustrated in FIG.4, the second actuator assembly 374 may comprise a hydraulic actuator.In an embodiment, the second actuator assembly 374 comprises the secondportion 362 of the third shaft 330. In an embodiment, the second portion362 may have a generally cylindrical shape defining a fluid conduit 376.The second portion 362 may also comprise one more radially extendingapertures 378 in fluid communication with both the fluid conduit 376 anda chamber 380. The chamber 380 may be defined by the second portion 362,a portion of the second clutch drum 360, the rotary sealing members334C, 334D, and a pressure plate 381. The second actuator assembly 374may also comprise a fluid reservoir (not depicted) in fluidcommunication with the fluid conduit 376. The fluid conduit 376 is influid communication with the chamber 380 via the one or more apertures378. When the fluid pressure in the chamber 380 is increased via a pump(not depicted), the pressure plate 381 is axially actuated tofrictionally engage the first and second pluralities of clutch plates370, 372 of the second clutch assembly 358.

A sixth gear 382 is coupled with the third shaft 330 and fixed forrotation therewith. The sixth gear 382 is in meshed engagement with aseventh gear 384. The seventh gear 384 is coupled with, and fixed forrotation with, a differential case 386. The differential case 386 ispart of a differential mechanism 388. The differential case 386 isrotatably supported within the axle housing 14 via bearings 390A, 390B.The differential mechanism 388 further includes two or more differentialpinions 392. The differential pinions 392 are coupled within thedifferential case 386 via a pinion shaft (i.e., spider shaft) (notdepicted). In an embodiment, the pinion shaft may comprise a crossmember. The differential pinions 392 are in meshed engagement with firstand second side gears 394A, 394B. The first side gear 394A is coupledfor rotation with the first axle shaft 16, and the second side gear 394Bis coupled for rotation with the second axle shaft 18. In operation,when a first speed ratio is desired, the first actuator assembly 344causes the first clutch assembly 326 to engage, while the second clutchassembly 358 remains disengaged. When the first clutch assembly 326 is25 engaged, the output shaft 306 of the electric motor 304 causes theoutput shaft 306 and the first gear 308 of the planetary gear assembly309 coupled thereto, to rotate therewith. Torque is transferred from theelectric motor 304 to the first gear 308. A rotation of the first gear308 drives the planet gears 312 and the planet carrier 314 coupledthereto. As such, the torque from the first gear 308 is then transferredto the planet carrier 314 via the planet gears 312. A rotation of theplanet carrier 314 causes the idler shaft 316, the second gear 322, andthe fifth gear 354 coupled thereto, to rotate therewith. The torque fromthe planet carrier 314 is then transferred to the idler shaft 316 to thesecond gear 322 and the fifth gear 354. The torque transferred from thefirst gear 308 to the second gear 322 and the fifth gear 354 isincreased because of the planetary gear assembly 309.

Because the first clutch assembly 326 is engaged, a rotation of thesecond gear 322 drives the third gear 324 of the compound idler assembly307. Hence, the torque is then transferred from the first gear 308 tothe third gear 324 via the second gear 322. A rotation of the third gear324 causes the idler shaft 330 and the sixth gear 382 coupled thereto,to rotate therewith. The torque from the third gear 324 is thentransferred to the idler shaft 330 via the first clutch assembly 326,and from the idler shaft 330 to the sixth gear 382.

A rotation of the sixth gear 382 drives the seventh gear 384 of thedifferential mechanism 388, and causes the differential case 386 torotate therewith. As such, the torque from the sixth gear 382 istransferred through the seventh gear 384 to the differential mechanism388. A rotation of the differential case 386 further causes the firstand second axle shafts 16, 18 to rotate therewith. The rotation of thedifferential mechanism 388 transfers a desired first torque from thedifferential mechanism 388 to the first and second axle shafts 16, 18.When the electric drive axle 300 is in a power generation mode, thetorque transfer described above is reversed.

In certain embodiments, the first speed ratio may also be referred to asa highway ratio. The first speed ratio enables the electric drive axleassembly 300 to operate at low torque and high speed.

When a second speed ratio is desired, the first clutch assembly 326 isdisengaged, while the second actuator assembly 374 causes the secondclutch assembly 358 to engage. When the second clutch assembly 358 isengaged, the output shaft 306 of the electric motor 304 causes theoutput shaft 306 and the first gear 308 coupled thereto, to rotatetherewith. Torque is transferred from the electric motor 304 to thefirst gear 308.

A rotation of the first gear 308 drives the planet gears 312 and theplanet carrier 314 coupled thereto. As such, the torque from the firstgear 308 is then transferred to the planet carrier 314 via the planetgears 312. A rotation of the planet carrier 314 causes the idler shaft316, the second gear 322, and the fifth gear 354 coupled thereto, torotate therewith. The torque from the planet carrier 314 is thentransferred to the idler shaft 316 to the second gear 322 and the fifthgear 354. The torque transferred from the first gear 308 to the secondgear 322 and the fifth gear 354 is increased because of the planetarygear assembly 309.

Because the second clutch assembly 358 is engaged, a rotation of thefifth gear 354 drives the fourth gear 356 of the compound idler assembly307. Hence, the torque is then transferred from the first gear 308 tothe fourth gear 356 via the fifth gear 354. A rotation of the fourthgear 356 causes the idler shaft 330 and the sixth gear 382 coupledthereto, to rotate therewith. The torque from the third gear 324 is thentransferred to the idler shaft 330 via the second clutch assembly 358,and from the idler shaft 330 to the sixth gear 382.

A rotation of the sixth gear 382 drives the seventh gear 384 of thedifferential mechanism 388, and causes the differential case 386 torotate therewith. As such, the torque from the sixth gear 382 istransferred through the seventh gear 384 to the differential mechanism388. A rotation of the differential case 386 further causes the firstand second axle shafts 16, 18 to rotate therewith. The rotation of thedifferential mechanism 388 transfers a desired first torque from thedifferential mechanism 388 to the first and second axle shafts 16, 18.When the electric drive axle 300 is in a power generation mode, thetorque transfer described above is reversed.

In certain embodiments, the second speed ratio may also be referred toas a crawl ratio. The second speed ratio enables the electric drive axleassembly 300 to operate at high torque and low speed.

Accordingly, the compound idler assembly 307 enables the electric driveaxle assembly 300 to achieve a drive ratio span facilitating urban,rural, and highway driving as well as towing and rock crawling.

In yet another embodiment shown in FIG. 5, the electric drive axle 400comprises an output shaft 406 disposed coaxially with axle shafts 16,18, and a compound idler assembly 407 disposed offset and parallel tothe output shaft 406 and the axle shafts 16, 18. In an embodiment, theelectric drive axle 400 comprises the output shaft 406 coupled with therotor of the electric motor 404 for rotation therewith. A first gear 408may be coupled with the output shaft 406 and fixed for rotationtherewith. In an embodiment, the first gear 408 is forged on the outputshaft 406. In another embodiment, the first gear 408 may be welded tothe output shaft 406. In still another embodiment, the first gear 408may be splined to the output shaft 406. The first gear 408 may be a sungear of a planetary gear assembly 409. The planetary gear assembly 409may further comprise two or more planet gears 412 in meshed engagementwith the first gear 408. The planet gears 412 may be rotatably disposedon planet pins (not depicted) coupled with a planet carrier 414. Theplanet carrier 414 may be coupled with a second shaft 416 and fixed forrotation therewith. The planet gears 412 may also be in meshedengagement with a ring gear 418 disposed at least partiallyconcentrically about the planet gears 412 and the first gear 408. Thering gear 418 may be coupled with a stationary structure such as theaxle housing 14, for example, and fixed thereto.

The second shaft 416 may be disposed coaxially with the output shaft 406and may be rotatably supported in the axle housing 14 via first andsecond bearings 420A, 420B. A second gear 422 is coupled with the secondshaft 416 and fixed for rotation therewith. The second gear 422 is inmeshed engagement with a third gear 424. The third gear 424 is coupledwith a first clutch drum 428 of a first clutch assembly 426. In certainembodiments, the compound idler assembly 407 includes the first clutchassembly 426. It is understood that the compound idler assembly 407 maybe rotatably supported in the axle housing 14 via third and fourthbearings 427A, 427B.

Additionally, the first clutch drum 428 disposed at least partiallyconcentrically within the third gear 424. A radially outer surface ofthe first clutch drum 428 is coupled with a radially inner surface ofthe third gear 424. In an embodiment, the first clutch drum 428 and thethird gear 424 may be coupled via splined engagement. In anotherembodiment, the first clutch drum 428 and the third gear 424 may becoupled via an interference fit. In yet another embodiment, the thirdgear 424 and the first clutch drum 428 may comprise a unitary component.The first clutch drum 428 is rotatably supported on a third shaft 430via fifth and sixth bearings 432A, 432B. Further, rotary sealing members434A, 434B are disposed adjacent to the roller bearings 432A, 432B,respectively, to create a substantially fluid-tight seal between aportion of the first clutch drum 428 and a first portion 436 of thethird shaft 430. The third gear 424 is entirely supported on the firstportion 436 by the first clutch drum 428.

A first clutch hub 438 is disposed at least partially concentricallywithin the first clutch drum 428. In an embodiment, the first clutch hub438 may be coupled for rotation with the first portion 436 of the thirdshaft 430. In an embodiment, the first clutch hub 438 may comprise asplined radially inner surface in meshed engagement with complimentarysplines on the first portion 436 of third shaft 430. In anotherembodiment, the first clutch hub 438 may be formed unitary and integralwith the first portion 436 of the third shaft 430.

A first plurality of clutch plates 440 are coupled for rotation with thefirst clutch drum 428. The clutch plates 440 receive torque from thefirst clutch drum 428 and may move axially within the first clutch drum428. A second plurality of clutch plates 442 are in meshed engagementwith the first clutch hub 438. The second plurality of clutch plates 442are interleaved with the first plurality of clutch plates 440. Thesecond plurality of clutch plates 442 may move axially on the firstclutch hub 438. The first clutch assembly 426 may be nested entirelywithin the third gear 424.

A first actuator assembly 444 may be utilized to selectively actuate thefirst clutch assembly 426. In an embodiment, as illustrated in FIG. 5,the first actuator assembly 444 may comprise a hydraulic actuator. In anembodiment, the first actuator assembly 444 comprises the first portion436 of the third shaft 430. In an embodiment, the first portion 436 mayhave a generally cylindrical shape defining a fluid conduit 446. Thefirst portion 436 may also comprise one more radially extendingapertures 448 in fluid communication with both the fluid conduit 446 anda chamber 450. The chamber 450 may be defined by the first portion 436,a portion of the first clutch drum 428, the rotary sealing members 434A,434B, and a pressure plate 452. The first actuator assembly 444 may alsocomprise a fluid reservoir (not depicted) in fluid communication withthe fluid conduit 446. The fluid conduit 446 is in fluid communicationwith the chamber 450 via the one or more apertures 448. When the fluidpressure in the chamber 450 is increased via a pump (not depicted), thepressure plate 452 is axially actuated to frictionally engage the firstand second pluralities of clutch plates 440, 442 of the first clutchassembly 426.

A fourth gear 454 is coupled with the second shaft 416 and fixed forrotation therewith. The fourth gear 454 is in meshed engagement with afifth gear 456. The fifth gear 456 is coupled with a second clutch drum460 of a second clutch assembly 458. In an embodiment, the second clutchassembly 458 comprises substantially the same components as the firstclutch assembly 426 and is operated in substantially the same manner.

The second clutch drum 460 is disposed at least partially concentricallywithin the fifth gear 456. A radially outer surface of the second clutchdrum 460 is coupled with a radially inner surface of the fifth gear 456.In an embodiment, the second clutch drum 460 and the fifth gear 456 maybe coupled via splined engagement. In another embodiment, the secondclutch drum 460 and the fifth gear 456 may be coupled via aninterference fit. In yet another embodiment, the fifth gear 456 and thesecond clutch drum 460 may comprise a unitary component. The secondclutch drum 460 is rotatably supported on the third shaft 430 viaseventh and eighth bearings 432C, 432D. Further, rotary sealing members434C, 434D are disposed adjacent to the bearings 432C, 432D,respectively, to create a substantially fluid-tight seal between aportion of the second clutch drum 460 and a second portion 462 of thethird shaft 430. The fifth gear 456 is entirely supported on the secondportion 462 by the second clutch drum 460.

A second clutch hub 468 is disposed at least partially concentricallywithin the second clutch drum 460. In an embodiment, the second clutchhub 468 may be coupled for rotation with a second portion 462 of thethird shaft 430. In an embodiment, the second clutch hub 468 maycomprise a splined radially inner surface in meshed engagement withcomplimentary splines on the second portion 462. In another embodiment,the second clutch hub 468 may be formed unitary and integral with thesecond portion 462 of the third shaft 430.

A first plurality of clutch plates 470 are coupled for rotation with thesecond clutch drum 460. The clutch plates 470 receive torque from thesecond clutch drum 460 and may move axially within the second clutchdrum 460. A second plurality of clutch plates 472 are in meshedengagement with the second clutch hub 468. The second plurality ofclutch plates 472 are interleaved with the first plurality of clutchplates 470. The second plurality of clutch plates 472 may move axiallyon the second clutch hub 468. The second clutch assembly 458 may benested entirely within the fifth gear 456.

A second actuator assembly 474 may be utilized to selectively actuatethe second clutch assembly 458. In an embodiment, as illustrated in FIG.4, the second actuator assembly 474 may comprise a hydraulic actuator.In an embodiment, the second actuator assembly 474 comprises the secondportion 462 of the third shaft 430. In an embodiment, the second portion462 may have a generally cylindrical shape defining a fluid conduit 476.The second portion 462 may also comprise one more radially extendingapertures 478 in fluid communication with both the fluid conduit 476 anda chamber 480. The chamber 480 may be defined by the second portion 462,a portion of the second clutch drum 460, the rotary sealing members434C, 434D, and a pressure plate 481. The second actuator assembly 474may also comprise a fluid reservoir (not depicted) in fluidcommunication with the fluid conduit 476. The fluid conduit 476 is influid communication with the chamber 480 via the one or more apertures478. When the fluid pressure in the chamber 480 is increased via a pump(not depicted), the pressure plate 481 is axially actuated tofrictionally engage the first and second pluralities of clutch plates470, 472 of the second clutch assembly 458.

A sixth gear 482 is coupled with the third shaft 430 and fixed forrotation therewith. In certain embodiments, the sixth gear 482 isdisposed axially outboard of the second clutch assembly 458. The sixthgear 482 is in meshed engagement with a seventh gear 484. The seventhgear 484 is coupled with, and fixed for rotation with, a differentialcase 486. The differential case 486 is part of a differential mechanism488. The differential case 486 is rotatably supported within the axlehousing 14 via bearings 490A, 490B. The differential mechanism 488further includes two or more differential pinions 492. The differentialpinions 492 are coupled within the differential case 486 via a pinionshaft (i.e., spider shaft) (not depicted). In an embodiment, the pinionshaft may comprise a cross member. The differential pinions 492 are inmeshed engagement with first and second side gears 494A, 494B. The firstside gear 494A is coupled for rotation with the first axle shaft 16, andthe second side gear 494B is coupled for rotation with the second axleshaft 18.

In operation, when a first speed ratio is desired, the first actuatorassembly 444 causes the first clutch assembly 426 to engage, while thesecond clutch assembly 458 remains disengaged. When the first clutchassembly 426 is engaged, the output shaft 406 of the electric motor 404causes the output shaft 406 and the first gear 408 of the planetary gearassembly 409 coupled thereto, to rotate therewith. Torque is transferredfrom the electric motor 404 to the first gear 408. A rotation of thefirst gear 408 drives the planet gears 412 and the planet carrier 414coupled thereto. As such, the torque from the first gear 408 is thentransferred to the planet carrier 414 via the planet gears 412. Arotation of the planet carrier 414 causes the idler shaft 416, thesecond gear 422, and the fifth gear 454 coupled thereto, to rotatetherewith. The torque from the planet carrier 414 is then transferred tothe idler shaft 416 to the second gear 422 and the fifth gear 454. Thetorque transferred from the first gear 408 to the second gear 422 andthe fifth gear 454 is increased because of the planetary gear assembly409.

Because the first clutch assembly 426 is engaged, a rotation of thesecond gear 422 drives the third gear 424 of the compound idler assembly407. Hence, the torque is then transferred from the first gear 408 tothe third gear 424 via the second gear 422. A rotation of the third gear424 causes the idler shaft 430 and the sixth gear 482 coupled thereto,to rotate therewith. The torque from the third gear 424 is thentransferred to the idler shaft 430 via the first clutch assembly 426,and from the idler shaft 430 to the sixth gear 482.

A rotation of the sixth gear 482 drives the seventh gear 484 of thedifferential mechanism 488, and causes the differential case 486 torotate therewith. As such, the torque from the sixth gear 482 istransferred through the seventh gear 484 to the differential mechanism488. A rotation of the differential case 486 further causes the firstand second axle shafts 16, 18 to rotate therewith. The rotation of thedifferential mechanism 488 transfers a desired first torque from thedifferential mechanism 488 to the first and second axle shafts 16, 18.When the electric drive axle 400 is in a power generation mode, thetorque transfer described above is reversed.

In certain embodiments, the first speed ratio may also be referred to asa highway ratio. The first speed ratio enables the electric drive axleassembly 400 to operate at low torque and high speed.

When a second speed ratio is desired, the first clutch assembly 426 isdisengaged, while the second actuator assembly 474 causes the secondclutch assembly 458 to engage. When the second clutch assembly 458 isengaged, the output shaft 406 of the electric motor 404 causes theoutput shaft 406 and the first gear 408 coupled thereto, to rotatetherewith. Torque is transferred from the electric motor 404 to thefirst gear 408.

A rotation of the first gear 408 drives the planet gears 412 and theplanet carrier 414 coupled thereto. As such, the torque from the firstgear 408 is then transferred to the planet carrier 414 via the planetgears 412. A rotation of the planet carrier 414 causes the idler shaft416, the second gear 422, and the fifth gear 454 coupled thereto, torotate therewith. The torque from the planet carrier 414 is thentransferred to the idler shaft 416 to the second gear 422 and the fifthgear 454. The torque transferred from the first gear 408 to the secondgear 422 and the fifth gear 454 is increased because of the planetarygear assembly 409.

Because the second clutch assembly 458 is engaged, a rotation of thefifth gear 454 drives the fourth gear 456 of the compound idler assembly407. Hence, the torque is then transferred from the first gear 408 tothe fourth gear 456 via the fifth gear 454. A rotation of the fourthgear 456 causes the idler shaft 430 and the sixth gear 482 coupledthereto, to rotate therewith. The torque from the third gear 424 is thentransferred to the idler shaft 430 via the second clutch assembly 458,and from the idler shaft 430 to the sixth gear 482.

A rotation of the sixth gear 482 drives the seventh gear 484 of thedifferential mechanism 488, and causes the differential case 486 torotate therewith. As such, the torque from the sixth gear 482 istransferred through the seventh gear 484 to the differential mechanism488. A rotation of the differential case 486 further causes the firstand second axle shafts 16, 18 to rotate therewith. The rotation of thedifferential mechanism 488 transfers a desired first torque from thedifferential mechanism 488 to the first and second axle shafts 16, 18.When the electric drive axle 400 is in a power generation mode, thetorque transfer described above is reversed.

In certain embodiments, the second speed ratio may also be referred toas a crawl ratio. The second speed ratio enables the electric drive axleassembly 400 to operate at high torque and low speed.

Accordingly, the compound idler assembly 407 enables the electric driveaxle assembly 400 to achieve a drive ratio span facilitating urban,rural, and highway driving as well as towing and rock crawling.

As illustrated in FIG. 6, in another embodiment, an electric drive axleassembly 500 comprises an output shaft 506, axle shafts 16, 18, and acompound idler assembly 512 disposed offset and parallel to the outputshaft 506 relative to each other. In certain embodiments, the outputshaft 506 is coupled with the rotor of the electric motor 504 forrotation therewith. The output shaft 506 shown is connected to aconcentric dual clutch 508. It should be appreciated that any type ofclutch 508 can be employed as desired such as a wet clutch assembly, asimple dog clutch assembly, a dog clutch assembly with a synchronizer,and the like, for example.

In the embodiment shown, the clutch 508 includes a first or outer clutchassembly 510 concentrically disposed about the output shaft 506 and asecond or inner clutch assembly 514 concentrically disposed about theoutput shaft 506 and radially within the first clutch assembly 510. Theclutch assemblies 510, 514 may be positioned radially adjacent to eachother such that a single actuator mechanism (not depicted) canseparately actuate each of the clutch assemblies 510, 514. Accordingly,only one of the clutch assemblies 510, 514 is engaged at any one time.The actuator mechanism can include an actuator, an additional gear setand a roller and ramp assembly. The actuator may be a reversibleelectric motor as it is compact and easily controllable. It isunderstood that any other appropriate type of actuator and actuatormechanism may be used such as hydraulic or pneumatic actuators, forexample.

In the embodiment shown, the first clutch assembly 510 includes a set ofclutch plates 516 extending radially inward from a first clutch hub 518.The clutch plates 516 are mounted for axial movement with the firstclutch hub 518. The first clutch assembly 510 further includes a secondclutch hub 520. The second clutch hub 520 has a set of clutch plates 522extending radially outward from the second clutch hub 520. The clutchplates 522 interleave with the clutch plates 516. It should beappreciated that the first clutch assembly 510 may include any number ofclutch plates 516, 522 as desired. The second clutch hub 520 isconnected to a common shaft 523. The common shaft 523 is disposedco-axially with the output shaft 506 and may be rotatably supported in astationary structure (e.g. the axle housing 14) by at least one bearing(not depicted). It is understood that the at least one bearing can beany type of bearing as desired such as a roller bearing, a ball bearing,a tapered bearing, and the like, for example.

A first gear 526 is coupled for rotation with the common shaft 523. Incertain embodiments, the first gear 526 may be a sun gear of a planetarygear assembly 529. The planetary gear assembly 529 may further comprisetwo or more planet gears 532 in meshed engagement with the first gear526. The planet gears 532 may be rotatably disposed on planet pins (notdepicted) coupled with a planet carrier 534. The planet carrier 534 maybe coupled with a second shaft 536 and fixed for rotation therewith. Theoutput shaft 506 and the second shaft 536 may be rotatably supported ina stationary structure such as the axle housing 14, for example, firstand second bearings 519A, 519B. It is understood that the at least onebearing can be any type of bearing as desired such as a needle bearing,a roller bearing, a ball bearing, a tapered bearing, and the like, forexample. The planet gears 532 may also be in meshed engagement with aring gear 538 disposed at least partially concentrically about theplanet gears 532 and the first gear 526. The ring gear 538 may becoupled with a stationary structure such as the axle housing 14, forexample, and fixed thereto. Accordingly, the electric motor 504 drivesthe first gear 526 of the planetary gear assembly 529 when the firstclutch assembly 510 is engaged.

As illustrated, the second clutch assembly 514 includes a set of clutchplates 528 extending radially inward from a first clutch hub 530. Theclutch plates 528 are mounted for axial movement with the first clutchhub 530. The second clutch assembly 514 further includes a second clutchhub 531 having a set of clutch plates 533 extending radially outwardfrom the second clutch hub 531. The clutch plates 533 interleave withthe clutch plates 528. It should also be appreciated that the secondclutch assembly 514 may include any number of clutch plates 528, 533 asdesired. A second gear 537 is drivingly connected to the second clutchassembly 514. In certain embodiments, the second gear 537 isconcentrically disposed about the second shaft 536 between the firstgear 526 and the second bearing 519B. Accordingly, the electric motor504 drives the second gear 537 when the second clutch assembly 514 isengaged.

In certain embodiments, the electric motor 504 drives the compound idlerassembly 512 via the planetary gear assembly 529 and the second gear 537when the first clutch assembly 510 is engaged, or via the second gear537 when the second clutch assembly 514 is engaged. As illustrated inFIG. 6, the compound idler assembly 512 is disposed parallel with theoutput shaft 506 of the electric motor 504. The compound idler assembly512 comprises an idler shaft 542 rotatably supported in the stationarystructure (e.g. the axle housing 14) via third and fourth bearings 544A,544B. It is understood that each of the bearings 544A, 544B can be anytype of bearing as desired such as a roller bearing, a ball bearing, atapered bearing, and the like, for example.

Third and fourth gears 550, 552, respectively, are coupled for rotationwith the idler shaft 542. The third gear 550 is disposed axiallyadjacent to the second bearing 544B. The fourth gear 552 is disposedaxially adjacent the first bearing 544A. The third gear 550 is in meshedengagement with the second gear 537 and receives torque therefrom whenone of the clutches 510, 514 is engaged and the electric motor 504drives the electric drive axle assembly 500. A pair of positioningelements (not depicted) may be respectively disposed on ends of theidler shaft 542 to maintain a position of the bearings 544A, 544B andthe third and fourth gears 550, 552. It is understood that each of thepositioning elements can be any type of positioning element as desiredsuch as a snap ring, for example but could use a shim and press fitbearings if the application allows for it.

As illustrated, the fourth gear 552 is in meshed engagement with a fifthgear 558. The fourth gear 552 drives the fifth gear 558, when one of thefirst and second clutches 510, 514, respectively, is engaged and theelectric motor 504 drives the electric drive axle assembly 500. Thefifth gear 558 is coupled for rotation with a differential mechanism560. The differential mechanism 560 is rotatably supported within thestationary structure (e.g. the axle housing 14) via a pair of bearings562A, 562B. It is understood that each of the bearings 562A, 562B can beany type of bearing as desired such as a roller bearing, a ball bearing,a tapered bearing, and the like, for example.

As illustrated in FIG. 6, the differential mechanism 560 includes two ormore differential pinions 566 disposed within a differential case 568.The differential pinions 566 are coupled with the differential case 568via a pinion shaft (not depicted). In an embodiment, the pinion shaftmay comprise a cross member. The differential pinions 566 are in meshedengagement with first and second side gears 570A, 570B. The first andsecond side gears 570A, 570B are coupled for rotation with the first andsecond half shafts 16, 18, respectively.

In operation, when a first speed ratio is desired, the first actuatorassembly causes the first clutch assembly 510 to engage, while thesecond clutch assembly 514 remains disengaged. When the first clutchassembly 510 is engaged, the output shaft 506 of the electric motor 504causes the output shaft 506 and the first gear 526 of the planetary gearassembly 529 coupled thereto, to rotate therewith. Torque is transferredfrom the electric motor 504 to the first gear 526. A rotation of thefirst gear 526 drives the planet gears 532 and the planet carrier 529coupled thereto. As such, the torque from the first gear 526 is thentransferred to the planet carrier 534 via the planet gears 532. Arotation of the planet carrier 534 causes the idler shaft 536 and thesecond gear 537 coupled thereto, to rotate therewith. The torque fromthe planet carrier 534 is then transferred through the idler shaft 536to the second gear 537. The torque transferred from the output shaft 506to the second gear 537 is increased because of the planetary gearassembly 529.

Because the first clutch assembly 510 is engaged, a rotation of thesecond gear 537 drives the third gear 550 of the compound idler assembly512. Hence, the torque is then transferred from the first gear 526through the planetary gear assembly 529 to the third gear 550 via thesecond gear 537. A rotation of the third gear 550 causes the idler shaft542 and the fourth gear 552 coupled thereto, to rotate therewith. Thetorque from the third gear 550 is then transferred through the idlershaft 542 to the fourth gear 552.

A rotation of the fourth gear 552 drives the fifth gear 558 of thedifferential mechanism 560, and causes the differential case 568 torotate therewith. As such, the torque from the fourth gear 552 istransferred through the fifth gear 558 to the differential mechanism560. A rotation of the differential case 568 further causes the firstand second axle shafts 16, 18 to rotate therewith. The rotation of thedifferential mechanism 560 transfers a desired first torque from thedifferential mechanism 560 to the first and second axle shafts 16, 18.When the electric drive axle 500 is in a power generation mode, thetorque transfer described above is reversed.

In certain embodiments, the first speed ratio may also be referred to asa crawl ratio. The first speed ratio enables the electric drive axleassembly 500 to operate at high torque and low speed.

When a second speed ratio is desired, the first clutch assembly 510 isdisengaged, while the second actuator assembly causes the second clutchassembly 514 to engage. When the second clutch assembly 514 is engaged,the output shaft 506 of the electric motor 504 causes the output shaft506 and the second gear 537 coupled to the idler shaft 536, to rotatetherewith. The torque transferred from the electric motor 504 to thesecond gear 537 remains unchanged.

Because the second clutch assembly 514 is engaged, a rotation of thesecond gear 537 drives the third gear 550 of the compound idler assembly512. Hence, the torque is then transferred from the first gear 526through the planetary gear assembly 529 to the third gear 550 via thesecond gear 537. A rotation of the third gear 550 causes the idler shaft542 and the fourth gear 552 coupled thereto, to rotate therewith. Thetorque from the third gear 550 is then transferred through the idlershaft 542 to the fourth gear 552.

A rotation of the fourth gear 552 drives the fifth gear 558 of thedifferential mechanism 560, and causes the differential case 568 torotate therewith. As such, the torque from the fourth gear 552 istransferred through the fifth gear 558 to the differential mechanism560. A rotation of the differential case 568 further causes the firstand second axle shafts 16, 18 to rotate therewith. The rotation of thedifferential mechanism 560 transfers a desired first torque from thedifferential mechanism 560 to the first and second axle shafts 16, 18.When the electric drive axle 500 is in a power generation mode, thetorque transfer described above is reversed.

In certain embodiments, the second speed ratio may also be referred toas a highway ratio. The second speed ratio enables the electric driveaxle assembly 500 to operate at low torque and high speed.

Accordingly, the compound idler assembly 512 enables the electric driveaxle assembly 500 to achieve a drive ratio span facilitating urban,rural, and highway driving as well as towing and rock crawling.

FIG. 7 illustrates an electric drive axle assembly 600. The electricdrive axle assembly 600 comprises an output shaft 606 and axle shafts16, 18 disposed coaxially with the output shaft 606. In certainembodiments, the output shaft 606 is coupled with the rotor of theelectric motor 604 for rotation therewith.

A first gear 608 may be coupled with the output shaft 606 and fixed forrotation therewith. In an embodiment, the first gear 608 is forged onthe output shaft 606. In another embodiment, the first gear 608 may bewelded to the output shaft 606. In still another embodiment, the firstgear 608 may be splined to the output shaft 606. The first gear 608 maybe a sun gear of a first planetary gear assembly 609. The firstplanetary gear assembly 609 may further comprise two or more planetgears 612 in meshed engagement with the first gear 608. The planet gears612 may be rotatably disposed on planet pins (not depicted) coupled witha planet carrier 614. The planet gears 612 may also be in meshedengagement with a ring gear 618 disposed at least partiallyconcentrically about the planet gears 612 and the first gear 608. Thering gear 618 may be selectively coupled with a stationary structuresuch as the axle housing 14, for example, via a first clutch assembly620. In certain embodiments, the ring gear 618 is coupled with a firstclutch drum 622 of the first clutch assembly 620.

As shown, a radially inner surface of the first clutch drum 622 iscoupled with a radially outer surface of the ring gear 618. In anembodiment, the first clutch drum 622 and the ring gear 618 may becoupled via splined engagement. In another embodiment, the first clutchdrum 622 and the ring gear 618 may be coupled via an interference fit.In yet another embodiment, the ring gear 618 and the first clutch drum622 may comprise a unitary component. A first clutch hub 624 is disposedat least partially concentrically within the first clutch drum 622. Afirst plurality of clutch plates 624 are coupled for rotation with thefirst clutch drum 622. The clutch plates 624 receive torque from thefirst clutch drum 622 and may move axially within the first clutch drum622. A second plurality of clutch plates 626 are in meshed engagementwith the stationary structure such as the axle housing 14, for example.The second plurality of clutch plates 626 are interleaved with the firstplurality of clutch plates 624. The second plurality of clutch plates626 may move axially on the stationary structure. A first actuatorassembly (not depicted) may be utilized to selectively actuate the firstclutch assembly 620. Various types of actuators may be employed as thefirst actuator assembly such as a hydraulic actuator, for example.

In certain embodiments, the planet carrier 614 may be coupled with aplanet carrier 628 of a second planetary gear assembly 630. The secondplanetary gear assembly 630 may further comprise two or more planetgears 632. The planet gears 632 may be rotatably disposed on planet pins(not depicted) coupled with the planet carrier 628. The planet gears 632may also be in meshed engagement with a ring gear 634 disposed at leastpartially concentrically about the planet gears 632. The ring gear 634may be selectively coupled with a stationary structure such as the axlehousing 14, for example, via a second clutch assembly 636. In certainembodiments, the ring gear 634 is coupled with a second clutch drum 638of the second clutch assembly 636.

As shown, a radially inner surface of the second clutch drum 638 iscoupled with a radially outer surface of the ring gear 634. In anembodiment, the second clutch drum 638 and the ring gear 634 may becoupled via splined engagement. In another embodiment, the second clutchdrum 638 and the ring gear 634 may be coupled via an interference fit.In yet another embodiment, the ring gear 634 and the second clutch drum638 may comprise a unitary component. A second clutch hub 640 isdisposed at least partially concentrically within the second clutch drum638. A first plurality of clutch plates 642 are coupled for rotationwith the second clutch drum 638. The clutch plates 642 receive torquefrom the second clutch drum 638 and may move axially within the secondclutch drum 638. A second plurality of clutch plates 644 are in meshedengagement with the stationary structure such as the axle housing 14,for example. The second plurality of clutch plates 644 are interleavedwith the first plurality of clutch plates 642. The second plurality ofclutch plates 644 may move axially on the stationary structure. A secondactuator assembly (not depicted) may be utilized to selectively actuatethe second clutch assembly 636. Various types of actuators may beemployed as the second actuator assembly such as a hydraulic actuator,for example.

In certain embodiments, the planet carrier 628 is coupled with, andfixed for rotation with, a differential case 646. The differential case646 is part of a differential mechanism 648. The differential case 646is rotatably supported within the axle housing 14 via bearings 650A,650B. The differential mechanism 648 further includes two or moredifferential pinions 652. The differential pinions 652 are coupledwithin the differential case 646 via a pinion shaft (i.e., spider shaft)(not depicted). In an embodiment, the pinion shaft may comprise a crossmember. The differential pinions 652 are in meshed engagement with firstand second side gears 654A, 654B. The first side gear 654A is coupledfor rotation with the first axle shaft 16, and the second side gear 654Bis coupled for rotation with the second axle shaft 18.

As illustrated in FIG. 7, in an embodiment, the first axle shaft 16 maybe coupled to third planetary gear assembly 656. In certain embodiments,the third planetary gear assembly 656 includes a sun or second gear 658coupled to the first axle shaft 16. The third planetary gear assembly656 shown may further comprise two or more planet gears 660 in meshedengagement with the second gear 658. The planet gears 660 may be inmeshed engagement with a ring gear 661 disposed at least partiallyconcentrically about the planet gears 660 and the second gear 658. Thering gear 661 may be coupled with a stationary structure such as theaxle housing 14, for example, and fixed thereto. The planet gears 660may also be rotatably disposed on planet pins (not depicted) coupledwith a planet carrier 662. The planet carrier 662 may be coupled with athird axle shaft 664 fixed for rotation therewith. The third axle shaft664 may be rotatably supported in a stationary structure such as theaxle housing 14, for example, by a bearing 666. It is understood thatthe bearing 666 can be any type of bearing as desired such as a needlebearing, a roller bearing, a ball bearing, a tapered bearing, and thelike, for example. In certain embodiments, the third axle shaft 664 maybe drivingly connected to a wheel 6 of the vehicle 10, shown in FIG. 1.

Similarly, the second axle shaft 18 may be coupled to fourth planetarygear assembly 670. In certain embodiments, the fourth planetary gearassembly 670 includes a sun or third gear 672 coupled to the second axleshaft 18. The fourth planetary gear assembly 670 shown may furthercomprise two or more planet gears 674 in meshed engagement with thethird gear 672. The planet gears 674 may be in meshed engagement with aring gear 676 disposed at least partially concentrically about theplanet gears 674 and the third gear 670. The ring gear 676 may becoupled with a stationary structure such as the axle housing 14, forexample, and fixed thereto. The planet gears 674 may also be rotatablydisposed on planet pins (not depicted) coupled with a planet carrier678. The planet carrier 678 may be coupled with a fourth axle shaft 679fixed for rotation therewith. The fourth axle shaft 679 may be rotatablysupported in a stationary structure such as the axle housing 14, forexample, by a bearing 680. It is understood that the bearing 680 can beany type of bearing as desired such as a needle bearing, a rollerbearing, a ball bearing, a tapered bearing, and the like, for example.In certain embodiments, the fourth axle shaft 679 may be drivinglyconnected to a wheel 8 of the vehicle 10, shown in FIG. 1.

In operation, when a first speed ratio is desired, the first actuatorassembly causes the first clutch assembly 620 to engage, while thesecond clutch assembly 636 remains disengaged. When the first clutchassembly 620 is engaged, the output shaft 606 of the electric motor 604causes the output shaft 606 and the first gear 608 of the firstplanetary gear assembly 609 coupled thereto, to rotate therewith. Torqueis transferred from the electric motor 604 to the first gear 608. Arotation of the first gear 608 drives the planet gears 612 and theplanet carrier 614 coupled thereto. As such, the torque from the firstgear 608 is then transferred to the planet carrier 614 via the planetgears 612. A rotation of the planet carrier 614 causes the secondplanetary gear assembly 630, and the differential mechanism 648 coupledthereto, to rotate therewith. The torque from the planet carrier 614 isthen transferred through the second planetary gear assembly 630 to thedifferential case 646. Because the first clutch assembly 620 is engaged,the torque transferred from the first gear 608 to the differentialmechanism 648 is increased because of the first planetary gear assembly609. The torque transferred from the planet carrier 614 through thesecond planetary gear assembly 630 remains unchanged because the secondplanetary gear assembly 630 freely rotates due to the second clutchassembly 636 being disengaged.

A rotation of the differential case 646 further causes the first andsecond axle shafts 16, 18 to rotate therewith. The rotation of thedifferential mechanism 648 transfers a desired first torque from thedifferential mechanism 648 to the first and second axle shafts 16, 18.

A rotation of the first axle shaft 16 causes a rotation of the secondgear 658 of the third planetary gear assembly 656 coupled thereto, torotate therewith. Torque is transferred from the axle shaft 16 to thesecond gear 658. A rotation of the second gear 658 drives the planetgears 660 and the planet carrier 662 coupled thereto. As such, thetorque from the second gear 658 is then transferred to the planetcarrier 662 via the planet gears 660. A rotation of the planet carrier662 causes the third planetary gear assembly 656, and the third axleshaft 664 coupled thereto, to rotate therewith. The torque from theplanet carrier 662 is then transferred through the third axle shaft 664to the wheel 6, shown in FIG. 1. When the electric drive axle 600 is ina power generation mode, the torque transfer described above isreversed.

In certain embodiments, the first speed ratio may also be referred to asa crawl ratio. The first speed ratio enables the electric drive axleassembly 600 to operate at high torque and low speed.

When a second speed ratio is desired, the second actuator assemblycauses the second clutch assembly 636 to engage, while the first clutchassembly 620 remains disengaged. When the second clutch assembly 636 isengaged, the output shaft 606 of the electric motor 604 causes theoutput shaft 606 and the first gear 608 of the first planetary gearassembly 609 coupled thereto, to rotate therewith. Torque is transferredfrom the electric motor 604 to the first gear 608. A rotation of thefirst gear 608 causes the planet carrier 614 of the first planetary gearsystem 609 and the planet carrier 628 of the second planetary gearsystem 630 to rotate. Since the second clutch assembly 636 is engaged,the torque from the first gear 608 is then transferred to the planetcarrier 628. A rotation of the planet carrier 628 causes thedifferential mechanism 648 coupled thereto, to rotate therewith. Thetorque from the planet carrier 628 is then transferred through thesecond planetary gear assembly 630 to the differential case 646. Becausethe first clutch assembly 620 is disengaged, the torque transferred fromthe first gear 608 to the differential mechanism 648 remains unchangedbecause the first planetary gear assembly 620 freely rotates.

A rotation of the differential case 646 further causes the first andsecond axle shafts 16, 18 to rotate therewith. The rotation of thedifferential mechanism 648 transfers a desired first torque from thedifferential mechanism 648 to the first and second axle shafts 16, 18.

A rotation of the second axle shaft 18 causes a rotation of the thirdgear 672 of the fourth planetary gear assembly 670 coupled thereto, torotate therewith. Torque is transferred from the axle shaft 18 to thethird gear 672. A rotation of the third gear 672 drives the planet gears674 and the planet carrier 678 coupled thereto. As such, the torque fromthe third gear 672 is then transferred to the planet carrier 678 via theplanet gears 674. A rotation of the planet carrier 678 causes the fourthplanetary gear assembly 670, and the fourth axle shaft 679 coupledthereto, to rotate therewith. The torque from the planet carrier 678 isthen transferred through the fourth axle shaft 679 to the wheel 8, shownin FIG. 1.

In certain embodiments, the second speed ratio may also be referred toas a highway ratio. The second speed ratio enables the electric driveaxle assembly 600 to operate at low torque and high speed.

Referring now to an embodiment shown in FIG. 8, the electric drive axleassembly 700 comprises an output shaft 706, axle shafts 16, 18, and acompound idler assembly 712 disposed offset and parallel to the motoroutput shaft relative to each other. In an embodiment, the electricdrive axle 700 comprises the output shaft 706 coupled with the rotor ofthe electric motor 704 for rotation therewith. The output shaft 706 isrotatably supported within a stationary structure such as the axlehousing 14, for example, by first and second bearings 707A, 707B. It isunderstood that the bearings 707A, 707B can be any type of bearing asdesired such as a roller bearing, a ball bearing, a tapered bearing, andthe like, for example. A first gear 708 may be coupled with the outputshaft 706 and fixed for rotation therewith. In an embodiment, the firstgear 708 is forged on the output shaft 706. In another embodiment, thefirst gear 708 may be welded to the output shaft 706. In still anotherembodiment, the first gear 708 may be splined to the output shaft 706.In certain embodiments, the first gear 708 is concentrically disposedabout the output shaft 706 axially adjacent the bearing 707A. A secondgear 710 is also coupled to the output shaft 706. In certainembodiments, the second gear 710 is concentrically disposed about theoutput shaft 706 axially adjacent the first gear 708.

In certain embodiments, as described in further detail hereinafter, theelectric motor 704 drives the compound idler assembly 712 via the firstgear 708 when one of a first clutch assembly 714 and a second clutchassembly 716 is engaged, or via the second gear 710 when a third clutchassembly 718 is engaged. As illustrated in FIG. 8, the compound idlerassembly 712 is disposed parallel with the output shaft 706 of theelectric motor 704. The compound idler assembly 712 comprises an idlershaft 720 rotatably supported in the stationary structure (e.g. the axlehousing 14) via third and fourth bearings 722A, 722B. It is understoodthat each of the bearings 722A, 722B can be any type of bearing asdesired such as a roller bearing, a ball bearing, a tapered bearing, andthe like, for example. A pair of positioning elements (not depicted) maybe respectively disposed on ends of the idler shaft 720 to maintain aposition of the bearings 722A, 722B. It is understood that each of thepositioning elements can be any type of positioning element as desiredsuch as a snap ring, for example but could use a shim and press fitbearings if the application allows for it.

A third gear 724 is concentrically disposed about the idler shaft 720axially adjacent to the third bearing 722A. The third gear 724 mayrotate relative to the idler shaft 720 via at least one bearing (notdepicted) disposed radially therebetween. It is understood that the atleast one bearing can be any type of bearing as desired such as a needlebearing, a roller bearing, a ball bearing, a tapered bearing, and thelike, for example. The third gear 724 is in meshed engagement with thefirst gear 724 and receives torque therefrom when the first clutchassembly 714 is engaged and the electric motor 704 drives the electricdrive axle assembly 700.

As illustrated, the first clutch assembly 714 is concentrically disposedabout the idler shaft 720. The third gear 724 is coupled with a firstclutch drum 728 of the first clutch assembly 714. In an embodiment, thefirst clutch drum 728 and the third gear 724 may be coupled via splinedengagement. In another embodiment, the first clutch drum 728 and thethird gear 724 may be coupled via an interference fit. In yet anotherembodiment, the third gear 724 and the first clutch drum 728 maycomprise a unitary component. The first clutch drum 728 is rotatablysupported on the idler shaft 720. Further, rotary sealing members (notdepicted) may be disposed adjacent to the first clutch assembly 714 tocreate a substantially fluid-tight seal between a portion of the firstclutch drum 728 and a first portion 736 of the idler shaft 720. Thethird gear 724 may be entirely supported on the first portion 736 by thefirst clutch drum 728.

A first clutch hub 738 is disposed at least partially concentricallywithin the first clutch drum 728. In an embodiment, the first clutch hub738 may be coupled for rotation with the first portion 736 of the idlershaft 720. In an embodiment, the first clutch hub 738 may comprise asplined radially inner surface in meshed engagement with complimentarysplines on the first portion 736 of the idler shaft 720. In anotherembodiment, the first clutch hub 738 may be formed unitary and integralwith the first portion 736 of the idler shaft 720.

A first plurality of clutch plates 740 are coupled for rotation with thefirst clutch drum 728. The clutch plates 740 receive torque from thefirst clutch drum 728 and may move axially within the first clutch drum728. A second plurality of clutch plates 742 are in meshed engagementwith the first portion 736 of the idler shaft 720. The second pluralityof clutch plates 742 are interleaved with the first plurality of clutchplates 740. The second plurality of clutch plates 742 may move axiallyon the first portion 736 of the idler shaft 720. The first clutchassembly 714 may be nested entirely within the third gear 724.

A first actuator assembly 744 may be utilized to selectively actuate thefirst clutch assembly 714. In an embodiment, as illustrated in FIG. 8,the first actuator assembly 744 may comprise a hydraulic actuator. In anembodiment, the first actuator assembly 744 comprises the first portion736 of the idler shaft 720. In an embodiment, the first portion 736 mayhave a generally cylindrical shape defining a fluid conduit 746. Thefirst portion 736 may also comprise one more radially extendingapertures 748 in fluid communication with both the fluid conduit 746 anda chamber 750. The chamber 750 may be defined by the first portion 736,a portion of the first clutch drum 728, the rotary sealing members, anda pressure plate 752. The first actuator assembly 744 may also comprisea fluid reservoir (not depicted) in fluid communication with the fluidconduit 746. The fluid conduit 746 is in fluid communication with thechamber 750 via the one or more apertures 748. When the fluid pressurein the chamber 750 is increased via a pump (not depicted), the pressureplate 752 is axially actuated to frictionally engage the first andsecond pluralities of clutch plates 740, 742 of the first clutchassembly 714. Accordingly, the electric motor 704 drives the third gear724 when the first clutch assembly 714 is engaged. It should beappreciated that any type of the first clutch assembly 714 can beemployed as desired such as a wet clutch assembly, a simple dog clutchassembly, a dog clutch assembly with a synchronizer, and the like, forexample.

In certain embodiments, the third gear 724 is coupled to a fourth gear754. As shown in FIG. 8, the third gear 724 and the fourth gear 754 maybe coupled to a common shaft 755 concentrically disposed about the idlershaft 720. The fourth gear 754 may be a sun gear of a planetary gearassembly 756. The planetary gear assembly 756 may further comprise twoor more planet gears 758 in meshed engagement with the fourth gear 754.The planet gears 758 may be rotatably disposed on planet pins (notdepicted) coupled with a planet carrier 760. The planet carrier 760 maybe coupled with a second portion 762 of the idler shaft 720 and fixedfor rotation therewith. The planet gears 758 may also be in meshedengagement with a ring gear 764 disposed at least partiallyconcentrically about the planet gears 758 and the fourth gear 754. Thering gear 764 may be selectively engaged with a stationary structuresuch as the axle housing 14, for example, via a second clutch assembly716.

The second clutch assembly 716 may comprise a second clutch hub 766coupled with the ring gear 764. The second clutch hub 766 may include aplurality of axially extending splines on a radially outer surfacethereof. A first plurality of clutch plates 768 are in meshed engagementwith the second clutch hub 766. The first plurality of clutch plates 768may move axially along the second clutch hub 766. The stationarystructure may comprise a second clutch drum 770 having a plurality ofaxially extending splines on a radially inner surface thereof. A secondplurality of clutch plates 772 are in meshed engagement with thestationary structure such as the axle housing 14, for example. Thesecond plurality of clutch plates 772 are interleaved with the firstplurality of clutch plates 768. The second plurality of clutch plates772 may move axially on the stationary structure. A second actuatorassembly (not depicted) may be utilized to selectively actuate thesecond clutch assembly 716. Various types of actuators may be employedas the second actuator assembly such as a hydraulic actuator, forexample.

A fifth gear 774 is coupled to the second portion 762 of the idler shaft720 for rotation therewith. The fifth gear 774 is in meshed engagementwith the second gear 710 and receives torque therefrom when the thirdclutch assembly 718 is engaged and the electric motor 704 drives theelectric drive axle assembly 700.

As illustrated, the third clutch assembly 718 is concentrically disposedabout the idler shaft 720. The fifth gear 774 is coupled with a thirdclutch drum 776 of the third clutch assembly 718. In an embodiment, thethird clutch drum 776 and the fifth gear 774 may be coupled via splinedengagement. In another embodiment, the third clutch drum 776 and thefifth gear 774 may be coupled via an interference fit. In yet anotherembodiment, the fifth gear 774 and the third clutch drum 776 maycomprise a unitary component. The first clutch drum 776 is rotatablysupported on the idler shaft 720. Further, rotary sealing members (notdepicted) may be disposed adjacent to the third clutch assembly 718 tocreate a substantially fluid-tight seal between a portion of the thirdclutch drum 776 and the second portion 762 of the idler shaft 720. Thefifth gear 774 may be entirely supported on the second portion 762 bythe third clutch drum 776.

A third clutch hub 778 is disposed at least partially concentricallywithin the third clutch drum 776. In an embodiment, the third clutch hub778 may be coupled for rotation with the second portion 762 of the idlershaft 720. In an embodiment, the third clutch hub 778 may comprise asplined radially inner surface in meshed engagement with complimentarysplines on the second portion 762 of the idler shaft 720. In anotherembodiment, the third clutch hub 778 may be formed unitary and integralwith the second portion 762 of the idler shaft 720.

A first plurality of clutch plates 780 are coupled for rotation with thethird clutch drum 776. The clutch plates 780 receive torque from thethird clutch drum 776 and may move axially within the third clutch drum776. A second plurality of clutch plates 782 are in meshed engagementwith the second portion 762 of the idler shaft 720. The second pluralityof clutch plates 782 are interleaved with the first plurality of clutchplates 780. The second plurality of clutch plates 782 may move axiallyon the second portion 762 of the idler shaft 720. The third clutchassembly 718 may be nested entirely within the fifth gear 774.

A third actuator assembly 784 may be utilized to selectively actuate thethird clutch assembly 718. In an embodiment, as illustrated in FIG. 8,the third actuator assembly 784 may comprise a hydraulic actuator. In anembodiment, the third actuator assembly 784 comprises the second portion762 of the idler shaft 720. In an embodiment, the second portion 762 mayhave a generally cylindrical shape defining a fluid conduit 786. Thesecond portion 786 may also comprise one more radially extendingapertures 787 in fluid communication with both the fluid conduit 786 anda chamber 788. The chamber 788 may be defined by the second portion 762,a portion of the third clutch drum 776, the rotary sealing members, anda pressure plate 790. The third actuator assembly 784 may also comprisea fluid reservoir (not depicted) in fluid communication with the fluidconduit 786. The fluid conduit 786 is in fluid communication with thechamber 788 via the one or more apertures 787. When the fluid pressurein the chamber 788 is increased via a pump (not depicted), the pressureplate 790 is axially actuated to frictionally engage the first andsecond pluralities of clutch plates 780, 782 of the third clutchassembly 718. Accordingly, the electric motor 704 drives the fifth gear774 via the second gear 710 when the third clutch assembly 718 isengaged. It should be appreciated that any type of the third clutchassembly 718 can be employed as desired such as a wet clutch assembly, asimple dog clutch assembly, a dog clutch assembly with a synchronizer,and the like, for example.

A sixth gear 791 is coupled for rotation with the idler shaft 720. Thesixth gear 791 shown is disposed axially adjacent to the fourth bearing722B. The sixth gear 791 from the first gear 708 when one of the clutchassemblies 714, 716 is engaged, and from the second gear 710 when thethird clutch assembly 718 is engaged and the electric motor 704 drivesthe electric drive axle assembly 700. As illustrated, the sixth gear 791is in meshed engagement with a seventh gear 792. The sixth gear 791drives the seventh gear 792 when one of the first, second, and thirdclutch assemblies 714, 716, 718 is engaged and the electric motor 704drives the electric drive axle assembly 700. The seventh gear 792 iscoupled for rotation with a differential mechanism 794. The differentialmechanism 794 is rotatably supported within the axle housing 14 via apair of bearings 796A, 796B. It is understood that each of the bearings796A, 796B can be any type of bearing as desired such as a rollerbearing, a ball bearing, a tapered bearing, and the like, for example.

As illustrated in FIG. 8, the differential mechanism 794 includes two ormore differential pinions 797 disposed within a differential case 798.The differential pinions 797 are coupled with the differential case 798via a pinion shaft (not depicted). In an embodiment, the pinion shaftmay comprise a cross member. The differential pinions 797 are in meshedengagement with first and second side gears 799A, 799B. The first andsecond side gears 799A, 799B are coupled for rotation with the first andsecond half shafts 16, 18, respectively, shown in FIG. 1.

In operation, when a first speed ratio is desired, the first actuatorassembly 744 causes the first clutch assembly 714 to engage, while thesecond clutch assembly 716 and the third clutch assembly 718 remaindisengaged. When the first clutch assembly 714 is engaged, the outputshaft 706 of the electric motor 704 causes the output shaft 706 and thefirst gear 708 and the second gear 710 coupled thereto, to rotatetherewith. Torque is transferred from the electric motor 704 to thefirst gear 708. A rotation of the first gear 708 drives the third gear724, and thereby the sixth gear 791 of the compound idler assembly 712.Hence, the torque is then transferred from the first gear 708 to thesixth gear 791 via the third gear 724. Since the first clutch assembly714 is engaged, the rotation of the third gear 724 causes the idlershaft 720 and the sixth gear 791 coupled thereto, to rotate therewith.The torque from the third gear 724 is then transferred to the idlershaft 720 via the first clutch assembly 714, and from the idler shaft720 to the sixth gear 791. The torque transferred from the third gear724 to the sixth gear 791 remains unchanged because the planetary gearassembly 756 and the fifth gear 774 freely rotate due to the second andthird clutch assemblies 716, 718, respectively, being disengaged.

A rotation of the sixth gear 791 drives the seventh gear 792 of thedifferential mechanism 794, and causes the differential case 798 torotate therewith. As such, the torque from the third gear 724 istransferred through the sixth gear 791 to the differential mechanism794. A rotation of the differential case 798 further causes the firstand second axle shafts 16, 18 to rotate therewith. The rotation of thedifferential mechanism 798 transfers a desired first torque from thedifferential mechanism 798 to the first and second axle shafts 16, 18.When the electric drive axle 700 is in a power generation mode, thetorque transfer described above is reversed.

In certain embodiments, the first speed ratio may also be referred to asa city ratio. The first speed ratio enables the electric drive axleassembly 700 to operate at medium torque and medium speed.

When a second speed ratio is desired, the second actuator assemblycauses the second clutch assembly 716 to engage, while the first clutchassembly 714 and the third clutch assembly 718 remain disengaged. Whenthe second clutch assembly 716 is engaged, the output shaft 706 of theelectric motor 704 causes the output shaft 706 and the first gear 708and the second gear 710 coupled thereto, to rotate therewith. Torque istransferred from the electric motor 704 to the first gear 708. Arotation of the first gear 708 drives the fourth gear 754 of theplanetary gear assembly 756, and thereby the sixth gear 791 of thecompound idler assembly 712. Hence, the torque is then transferred fromthe first gear 708 to the sixth gear 791 via the planetary gear assembly756. Since the first clutch assembly 714 is disengaged and the secondclutch assembly 716 is engaged, the rotation of the third gear 724causes the common shaft 755 and the fourth gear 754 coupled thereto, torotate therewith. The torque from the third gear 724 is then transferredthrough the idler shaft 720 to the fourth gear 754 via the second clutchassembly 714.

A rotation of the fourth gear 754 drives the planet gears 758 and theplanet carrier 760 coupled thereto. As such, the torque from the fourthgear 754 is then transferred to the planet carrier 760 via the planetgears 758. A rotation of the planet carrier 414 causes the idler shaft720 and the sixth gear 791 coupled thereto, to rotate therewith. Thetorque from the planet carrier 760 is then transferred to the idlershaft 720 via the second clutch assembly 716 to the sixth gear 791. Thetorque transferred from the first gear 408 through the second and thirdgears 724, 754 to the sixth gear 791 is increased because of theplanetary gear assembly 756.

A rotation of the sixth gear 791 drives the seventh gear 792 of thedifferential mechanism 794, and causes the differential case 798 torotate therewith. As such, the torque from the third gear 724 istransferred through the sixth gear 791 to the differential mechanism794. A rotation of the differential case 798 further causes the firstand second axle shafts 16, 18 to rotate therewith. The rotation of thedifferential mechanism 798 transfers a desired first torque from thedifferential mechanism 798 to the first and second axle shafts 16, 18.When the electric drive axle 700 is in a power generation mode, thetorque transfer described above is reversed.

In certain embodiments, the second speed ratio may also be referred toas a crawl ratio. The second speed ratio enables the electric drive axleassembly 700 to operate at high torque and low speed.

When a third speed ratio is desired, the third actuator assembly 784causes the third clutch assembly 718 to engage, while the first clutchassembly 714 and the second clutch assembly 716 remain disengaged. Whenthe third clutch assembly 718 is engaged, the output shaft 706 of theelectric motor 704 causes the output shaft 706 and the first gear 708and the second gear 710 coupled thereto, to rotate therewith. Torque istransferred from the electric motor 704 to the second gear 710. Arotation of the second gear 710 drives the fifth gear 774, and therebythe sixth gear 791 of the compound idler assembly 712. Hence, the torqueis then transferred from the second gear 708 to the sixth gear 791 viathe fifth gear 774. Since the third clutch assembly 718 is engaged, therotation of the fifth gear 774 causes the idler shaft 720 and the sixthgear 791 coupled thereto, to rotate therewith. The torque from the fifthgear 774 is then transferred to the idler shaft 720 via the third clutchassembly 718, and from the idler shaft 720 to the sixth gear 791. Thetorque transferred from the fifth gear 774 to the sixth gear 791 remainsunchanged because third gear 724 and the planetary gear assembly 756freely rotate due to the first and second clutch assemblies 714, 716,respectively, being disengaged.

A rotation of the sixth gear 791 drives the seventh gear 792 of thedifferential mechanism 794, and causes the differential case 798 torotate therewith. As such, the torque from the third gear 724 istransferred through the sixth gear 791 to the differential mechanism794. A rotation of the differential case 798 further causes the firstand second axle shafts 16, 18 to rotate therewith. The rotation of thedifferential mechanism 798 transfers a desired first torque from thedifferential mechanism 798 to the first and second axle shafts 16, 18.When the electric drive axle 700 is in a power generation mode, thetorque transfer described above is reversed.

In certain embodiments, the third speed ratio may also be referred to asa highway ratio. The third speed ratio enables the electric drive axleassembly 700 to operate at low torque and high speed.

Accordingly, the compound idler assembly 712 enables the electric driveaxle assembly 700 to achieve a drive ratio span facilitating urban,rural, and highway driving as well as towing and rock crawling.

One or more features of the embodiments described supra may be combinedto create additional embodiments which are not depicted. While variousembodiments have been described above, it should be understood that theyhave been presented by way of example, and not limitation. It will beapparent to persons skilled in the relevant arts that the disclosedsubject matter may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The embodimentsdescribed above are therefore to be considered in all respects asillustrative, not restrictive.

What is claimed is:
 1. An axle assembly, comprising: an electric motorhaving an output shaft; at least one of a gear and a first planetarygear assembly connected to the output shaft; a differential mechanismconnected with the at least one of the gear and the first planetary gearassembly, wherein the differential mechanism is connected to at leastone axle shaft; a first clutch assembly connected with at least one ofthe output shaft and the differential mechanism, wherein an engagementof the first clutch assembly produces a first speed ratio; a secondclutch assembly connected with at least one of the output shaft and thedifferential mechanism, wherein an engagement of the second clutchassembly produces a second speed ratio; a second planetary gear assemblyconnected to the output shaft; and a third planetary gear assemblyconnected to the at least one axle shaft.
 2. The axle assembly of claim1, wherein the first planetary gear assembly is selectively connected tothe output shaft by the first clutch assembly.
 3. The axle assembly ofclaim 2, wherein the second planetary gear assembly is selectivelyconnected to the output shaft by the second clutch assembly.
 4. The axleassembly of claim 1, wherein the second planetary gear assembly isconnected to the first planetary gear assembly.
 5. The axle assembly ofclaim 1, wherein the first planetary gear assembly comprises a firstplanet carrier, the second planetary gear assembly comprises a secondplanet carrier, and the first and second planet carriers are connectedto one another.
 6. The axle assembly of claim 1, wherein the at leastone axle shaft is coaxially aligned with the output shaft.
 7. The axleassembly of claim 1, further comprising a fourth planetary gear assemblyconnected to the at least one axle shaft.
 8. The axle assembly of claim7, wherein the first, the second, the third, and the fourth planetarygear assemblies are coaxially aligned with the output shaft.
 9. The axleassembly of claim 8, wherein the first and second planetary gearassemblies are coaxially aligned with the output shaft between thedifferential mechanism and the electric motor, and the third and fourthplanetary gear assemblies are coaxially aligned with the output shaftwith the differential mechanism and the electric motor therebetween. 10.A method, comprising: providing an axle assembly including: an electricmotor having an output shaft; at least one of a gear and a firstplanetary gear assembly connected to the output shaft; a differentialmechanism connected with the at least one of the gear and the firstplanetary gear assembly, wherein the differential mechanism is connectedto at least one axle shaft; a first clutch assembly connected with atleast one of the output shaft and the differential mechanism, wherein anengagement of the first clutch assembly produces a first speed ratio; asecond clutch assembly connected with at least one of the output shaftand the differential mechanism, wherein an engagement of the secondclutch assembly produces a second speed ratio; a second planetary gearassembly connected to the output shaft; and a third planetary gearassembly connected to the at least one axle shaft; and causing theengagement of one of the first clutch assembly and the second clutchassembly.
 11. The method of claim 10, wherein the engagement of thefirst clutch assembly produces the first speed ratio and engagement ofthe second clutch assembly produces the second speed ratio.
 12. An axleassembly, comprising: an electric motor having an output shaft; at leastone of a gear and a first planetary gear assembly connected to theoutput shaft; a differential mechanism connected with the at least oneof the gear and the first planetary gear assembly, wherein thedifferential mechanism is connected to at least one axle shaft; a firstclutch assembly connected with at least one of the output shaft and thedifferential mechanism, wherein an engagement of the first clutchassembly produces a first speed ratio; a second clutch assemblyconnected with at least one of the output shaft and the differentialmechanism, wherein an engagement of the second clutch assembly producesa second speed ratio; and a third clutch assembly connected with atleast one of the output shaft and the differential mechanism, wherein anengagement of the third clutch assembly produces a third speed ratio,and wherein one of the first clutch assembly, the second clutchassembly, and the third clutch assembly is connected to the firstplanetary gear assembly.
 13. The axle assembly of claim 12, furthercomprising an idler shaft rotationally connected to at least one of theoutput shaft and the differential mechanism.
 14. The axle assembly ofclaim 13, wherein the output shaft, the idler shaft, and the axle shaftare offset from one another.
 15. The axle assembly of claim 12, whereinthe second clutch assembly includes a plurality of plates connected to asecond gear in the planetary gear assembly.
 16. The axle assembly ofclaim 15, wherein the second gear is a ring gear.
 17. The axle assemblyof claim 14, wherein the first, the second, and the third clutchassemblies are coaxially aligned with the idler shaft.
 18. The axleassembly of claim 13, wherein the first clutch assembly includes a firstplurality of clutch plates rotationally connected to the idler shaft.19. The axle assembly of claim 18, wherein the third clutch assemblyincludes a second plurality of clutch plats rotationally connected tothe idler shaft.
 20. The axle assembly of claim 19, wherein the secondclutch assembly includes a plurality of plates connected to a ring gear,and the second clutch assembly is coaxially aligned on the idler shaftbetween the first clutch assembly and the third clutch assembly.